This little stucco house, in the Woodstock neighborhood, is one of Julie’s favorites. It sits on a little rise clothed in an unbroken sea of Juniperus sabina Tamariscifolia (?) punctuated with several Italian Cypress. This landscape has been here for decades and appears to be completely weed free. It’s xeric with enough density to choke out weedy interlopers.  By not adding supplemental water many of our more common weeds are discouraged. Even if you wanted to apply a pre-emergent herbicide I don’t know if it could get to the soil. There is no way for anyone to enter this to remove volunteer Blackberries, Clematis, Canada Thistle or anything else for that matter. Junipers are strongly allelopathic containing chemicals in their shed foliage that build up in the organic layer on the soil surface discouraging successful weed germination.  Many other plants including our West coast Manzanita are allelopathic as well and can be used similarly.  Generally, allelopathic plants require several years to build up an effective layer of weed controlling old leaves to be effective, so our efforts will be necessary for some time.  At minimum don’t remove this layer of old and decaying leaves!  Junipers are also highly competitive in terms of their roots for water and nutrients.  Do I recommend this landscape…not necessarily, as it provides little ‘useful’ space offering little more than a very ‘defensible’ border, though it does have its attraction.   It provides shelter for some birds and critters, including rats, unfortunately, and fruit to those interested, while posing a minimal weed/seeding hazard to other landscapes.  It is a very simple landscape.

We can do much better than we have been doing with our landscapes…we have to!  It is incumbent upon each of us to grow our landscapes well, whatever they are, whatever they demand of us.  Our inability or unwillingness to do this is symptomatic of a society today that doesn’t  place priority and value on life, first!  (If you are reading this, you probably aren’t part of this ‘we’.)  The fact that we don’t have the time, resources or interest is indicative of how far out of balance our own lives are.  This isn’t a new phenomenon.  I don’t mean to shame or blame anyone here.  Modern societies have long been out of step.  We place a premium on our personal freedom, the idea that we have moved beyond nature, that technology will do for us whatever we need.  Nature will keep ‘chugging’ on without us so that we can devote ourselves to our more personal goals…and so ‘nature’ has been left largely on its own as if what we do will have no significant or damaging effects…but that isn’t really the way it is.  So, what do we do about that dead weedy lawn out front?

There is a popular misconception that if ‘we’ didn’t do something then it’s outcome is an ‘act of nature’ and, is as it should be, or is ‘working’ toward a ‘natural’ solution.  One of these is that the proliferation of weeds in modern cities is a natural, healing ‘response’.  This idea is part of the same belief that got us here. This view absolves us of our responsibility and necessary roles.  It is child like.

What you ‘choose’ to do with your degraded lawn, should be approached much like any other landscape question: first, where do you live and exactly what are the growing conditions; second, what do you want, in terms of function, how do you plan to use the space and, what do you want it to look like; and third, the ‘resources’, including time, knowledge, experience and physical ability that you have at your disposal to implement this…including for maintenance over the long term.  There is no simple recipe that can be implemented and ‘solve’ your problem.  Every solution will be different, unique.  We don’t all have the same goals and our commitment and resources available to us vary widely.  The fact that droughted, degraded, lawns are so common across our urban landscapes speaks volumes about our understanding and commitment toward ‘solving’ this problem.  It includes residents, businesses, institutions and government agencies. It is important as well to understand that these three factors, site conditions, goals and resources, may not be in alignment, what we ‘want’, especially given our site conditions, may require more than we are willing or able to commit.  Also, what we want, in terms of plants, may be in conflict with how we will use the space.  This is very common when attempting to solve any problem when our own knowledge and experience are limited.

A closer neighbor of mine got uncharacteristically ambitious and removed 3 Juniperus sabina Tamariscifolia here that were encroaching on the sidewalk and inhibiting car access.

He left this one. It is mostly buried beneath Clematis vitalba and sports a prominent Hazel along with a young Black Walnut and Tree of Heaven. Part of the issue here is the narrowness of the planting and a long ‘edge’ with thin cover that has allowed aggressive and strong growing species to gain a foothold. Now that these are established all will dominate if allowed and will overtop the Juniper weakening it.

Where do you live?

I spent much of my previous ‘lawn’ postings on the general conditions inherent to the typical lawn setting In Portland and I won’t rehash them here.  I have dedicated earlier postings to soil conditions and the movement of water through it and into plants.  I cannot stress enough how vital the specific growing conditions on a site are.  I have also written earlier how typical urban conditions are radically different than those that existed prior to ‘our’ arrival and our initial disruption of the landscapes here.  Modern development, with its grading, hard surfaces and heavy human use have forever transformed our landscapes, and the possibilities to come.  It is important to understand that the typical urban site is so degraded, is still subject to routine and continuous disturbance and isolated from the larger landscape that each ‘works’ more as an individual site than as a coherent, integrated broader landscape, that each stands on its own, resisting the pressures and invasions launched by the others.  It is not possible to simply go to a local nursery, select from the available native plants, plant them on your site, even if light and shade conditions are met, and walk away.

Many properties don’t support the woodland landscape that was once common here, because stripped of their trees long ago and their humus rich top layer of soil depleted, all but the toughest woodlanders will decline on them.  Many of our native woodlanders are to some degree obligate, meaning, the conditions that they require are those of a woodland, they will not survive without them, so they cannot be planted before those conditions exist.  We must plan and work toward a goal that will be years in the making.  Nature does not transform ‘herself’ over night.  It can take generations of growth and development over which new communities can form and transform, including the conditions on their sites…and our actions must support them!

Sun, shade and aspect, are relatively easy to assess.  Which way does the site face?  Which hours of the day does it receive sun and what is its intensity?  How does this change over the year?  Structures shade a site more like a rocky cliff face than a tree…they also change the surface and sub-surface drainage and movement of water.  Modern construction effectively chops the landscape up into discrete, disconnected planters each with a limited soil volume and water capacity that must be considered when planting.  Combine this with human activity, foot and occasional, or frequent, vehicular traffic and the compaction it causes, which effectively reduces the available soil depth, because if the roots can’t penetrate it, it is of no use, and you have an even more limited environment for your plants.

Keep in mind that when we build structures and hard surfaces today we intentionally compact the soil beneath and around them to stabilize them over time.  Topsoil, depleted, degraded or not, is commonly scraped off of building sites to meet surface drainage needs.  Shifting slabs and foundations must be limited to protect the structures…which works against the landscape.  These compromised and contained soils can dry out much more quickly than a similarly sized undisturbed site.  Over our rainy winter season, these same sites may function more like bowls, collecting and holding water, effectively saturating the root zone of any plants growing in them over the wet season.

Iris x pacifica well grown in my garden. This is a rhizomatous grower and can be quite thick, but if its neighbors are stronger growing this will get choked out and weakened. You have to tilt the ‘field’ in the favor of your plants.

Geranium x cantabrigiense can make a nice, weed suppressing ground cover if you give it enough water. It isn’t very ‘thirsty’, but it has its needs. Larger more aggressive weeds can invade it, but I use it in my garden. Geranium macrorrhizum, one of its parents, does the same, only it is a larger plant and is more effective on larger weeds. It is a balancing act. The rhizomes of each are relatively easy to remove if need be unlike a lot of other rhizomatous spreaders.

Mondo Grass, Ophiopogon japonicus, is in the foreground with Acorus gamineus ‘Ogon’, left background. Both are rhizomatous. The Ophiopogon forms a deeper ‘turf’ structure above and below ground. Neither spreads quickly but they do spread and must be monitored to keep them from engulfing less vigorous plants that they might otherwise choke out.

What do you want?

This question requires that we be honest with ourselves.  It requires that we make choices because every choice eliminates other possibilities.  It requires some degree of maturity on our part.  It will cause us endless frustration and expenditures if we attempt to create something that does not fit our particular site conditions, if what we use the space for is damaging to the plants directly or to the site conditions they rely upon and/or if we are not realistically committed to them in terms of maintenance.

Lawns provide us with either an active or passive outdoor space that is open, comfortable  and ‘safe’ for what we do there.  Turf grass, as I explained elsewhere, has proven to be the ‘best’ surface treatment for this kind of space…if we take care of it.  There are a variety of turf alternatives out there, all of which are inferior to good grass turf.  This is why we grow it.  Obviously other plants can be planted uniformly as a single species cover and they will in fact ‘cover’ the soil.  Some can be very good weed suppressors…again, if their needs are met.  If they aren’t, like Perennial Rye Grass, they will collapse and yield to aggressive and more drought adapted species.  None of these other turf alternatives have proven to be as durable as good grass turf when regular physical activity occurs on them.  Depending on the plant they will fail under use.  If these areas are put to extremely limited use, including very little foot traffic, then they may hold up.  Because of the low crown height of good turf grasses, their vigor and ability to tiller, they are able to recover from the routine damage that foot traffic does to a plant’s top growth, but even then, only if it isn’t too heavy.

Usually we call these ground covers because that is what they are intended to do, cover the ground.  They are not for active human use.  Plants like Vinca minor, Hedera spp. and some of the spreading Geraniums like macrorrhizum and x cantabrigiense are very good at this… some are ‘too’ good at it.  There are turf alternatives touted out there like ‘micro-clover’ that require less water, fertilizer and mowing in our region, but can present a further complication for the gardener or landscape maintenance staff because of their ability to spread.  Aggressively spreading ‘ground covers’ behave much like many of our low spreading weeds making them difficult to contain and keep out of beds and other plantings.  Their success as ground covers is the same thing that makes them problematic in the landscape.  There is a fine line between a weed and a ground cover.

Plants that make good ground covers share many characteristics with a good grass lawn.  Whereas grasses like Perennial Rye spread via tillering many other plants produce stolons or rhizome forming ‘new’ plants from the nodes on them.  Those that do this densely enough can make effective, weed suppressing ground covers.  This includes many other grasses and their relatives as well as ‘dicots’.  Some of these have been commonly use for this in the trade and, unfortunately, even under conditions that they can’t perform with.  In the end you always have to consider the needs of the plant first.  If they don’t match those that you can provide for it, choose something else!

Some low shrubs, like the Juniperus sabina ‘Tamarqscifolia’ I described above, can be very effective as well.  The important thing is for a plant or matrix planting to have enough density and vigor to out compete area weeds, not leaving any niches for theme to take advantage of.

A landscape can take advantage of multiple choices within a group.  You needn’t rely on only one ground cover.  In fact choosing several provides you ‘insurance’.  As the conditions change, even minimally across a site, one or the other may predominate.  Planting in a matrix pattern, a mix of plants with shared requirements, while filling different niches, some taller than others, some spring ephemerals others that come into prominence later in the season, can give your overall planting more stability with plants that you’ve chosen playing a more dominate role where they can and letting others take the lead where they can’t.  This should be one of the goals of any ‘low maintenance’ landscapes, filling as many of the niches as they can and thereby reducing the impact of weeds.  One will, of course, always have to remain vigilant and continue monitoring and acting in a manner that is minimally disruptive and timely as well.

Delosperma congesta, one of the many Ice Plants, makes a low cover here on full sun sites with only occasional summer irrigation. I don’t have to weed this. It’s competition as a small Sedum and the low Yellow Flowred Oxalis that hasn’t actually moved into the Delosperma…yet!

My favorite California Fuchsia, I’m still calling Zauschneria septentrionalis ‘Select Mattole’. This makes a magnificent ground cover in full sun, xeric, landscapes. Its recent shift to genus Epilobium speaks to its ‘weedy’ nature, or rather its ability to move. While it does spread I haven’t seen this or any other selection seed around here. So, yes it will move where it wants so like most any rhizomatous plant you should pay attention to what you plant it next to.

Stachys byzantina ‘Primrose Heron’ an old selection of the long used Lamb’s Ear is another durable, sun tolerant, xeric ground cover that I’ve had somewhere on my hell strip for the past 25 years.

Sedum palmeri, loves my front bank, with a little bit of shade and an occasional squirt, that makes my Agave parryi Hauchuca Blue, equally ‘happy’. In this immediate area I’ve planted Asurina procumbens which is able to fill in the shadier areas on this bank.

Perennial Rye Grass is considered by many ecologists to be a threat to native landscapes.  If it is well maintained, including mowing to prevent it from going to seed and the turf is regularly edged to keep it from expanding into beds, I would argue that it is very manageable and its invasion level is relatively low compared to many of the alternatives out there being promoted and used.  Many of the ‘alternatives’ require less routine maintenance, less fertilizer, less frequent mowings, because they are so well adapted to our region.  They often have lower stature and will flower and set seed at a much lower height allowing them to spread readily.  Too often the plants chosen for alternative turf blends and ground covers are exotic as well and are capable of readily moving into adjacent landscapes and beds.  If you are looking for a lower maintenance solution, a meadow type of landscape, I would strongly urge you to use local species.  (Meadows aren’t low maintenance here, they require rather, a different kind of maintenance.)  This way if they do begin to seed about, which is to some degree desirable, you won’t be promoting the spread of exotic weeds around the neighborhood.

Traditionally lawns tend to cover a large portion of a site on a given property.  They tend to be exposed.  Converting them to a meadow is a very viable option, but this must be done in a manner that recognizes the conditions on the site.  They are not plant and go.  They are also, perhaps surprisingly to many, very complex, containing multiple grass species and, additionally, many species comprise the forbs component.  [Forbs are herbaceous flowering plants that are not graminoids (grasses, sedges and rushes). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory.]  The sometimes commercially available wildflowers or meadows in a ‘can’, with their one size fits all kind of approach is not a responsible option.  They will also likely fail especially if inadequate consideration has been given to seed already on site in the soil and being added from adjacent properties.  The meadow in a can approach is a ‘product’ that is relatively widely marketed and because of this is not ‘tailored’ to ‘your’ conditions.  If you consider one of these, find out first just where the purportedly native wildflowers that they contain are actually native to.  A wildflower native to  the Pacific Northwest still doesn’t mean it is a good choice for your site.  Remember, Oregon contains landscape types from coastal salt marsh to alpine meadows, from vernal Willamette Valley meadow to high desert Juniper steppe.  If you don’t make good choices, the weeds will do it for you.

Meadows are also difficult for two other reasons, first, is the amount of solar energy striking the soil surface powering growth over our long growing season and second is the difficulty of discerning desirable native grass species from the many aggressive Eurasian species common here now that can dominate the natives.  This doesn’t mean you shouldn’t attempt this, it just stresses the importance of understanding what you are trying to do and ‘equipping’ yourself to be successful.

This meadow was installed around ’05 in Tanner Springs Park. From the beginning the site was subject to invasion by the exotic Holcus lanatus, Velvet Grass, several other weedy grass species and Canada Thistle, Vetch, Dutch White Clover, Cat’s Ear and others. Its maintenance has been problematic. More recently a group of volunteers has formed to work on the site moving it to a more stable meadow community.  In the meadow here in the foreground is an Aesculus californica with an Amelanchier, taken this past Spring, ’17, blooming in the background.  This picture of a meadow in a dense urban area doesn’t really show the conflict presented by just this circumstance, many people using a landscape that is intolerant of their active use.  Each person walking, romping, sitting in or running through it flattens it for the season.  People do seem to be ‘learning’ to respect it.

In my experience a mixed more layered landscape takes advantage of more of the energy striking the ground and is easier to monitor and ‘read’ making them somewhat easier to manage over time.   Part of this is due to the variety of plant types.  Others may find a meadow of multiple grass species less confusing than I do and will be fine with this.  Historically, in the Willamette Valley, meadow and savannah landscapes were supported by periodic fires that destroyed the trees and shrubs that would otherwise turn them into a woodland.  Exposed sunny sites can be converted into a variety of other landscapes containing various woody species, e.g., savannah, woodland, chaparral or a more ‘productive’ landscape dedicated to food production or cut flowers or a more special collection.  People need to make a considered, thoughtful, choice.  No landscape can be all things.

Many people attempt to grow lawns beneath a tree canopy which intercepts the light that a healthy grass lawn requires.  Moss moves in.  Often lawns were planted along with immature small trees, that cast progressively increasing shade as they grow and whose roots, especially if they are shallow rooted species like Maples and Elms, compete aggressively for water and nutrients with the grass and other plants.  Owners often attempt to keep a lawn long after shade has begun to dominate it, out of habit and/or because they want to maintain the area as a functional open space for their activities.  Grass requires sunlight.  Shade limits durability even if you plant a shade ‘tolerant’ Fescue variety.  This presents the landowner with a choice of reducing the shade either by tree removal or radically thinning the canopy, or converting the lawn into a shade tolerant, more woodland type landscape, adding appropriate woodlanders that can occupy niches otherwise filled by weeds.

There are purportedly other ‘grass’ alternatives to the lawn.  Some of these are evergreen Carex species…just be aware that these too are a compromise and will likely be less tolerant of regular foot traffic.  Also keep in mind that some of these are bunching type growers and, as I’ve said elsewhere, will leave open physical space in-between them that are subject to weed invasion.  Some will take on a ‘hummocky’ appearance that is reminiscent of wet alpine or lakeside meadows, not a problem if you don’t intend to play croquet.  Like true grasses, if these are combined, blended with other complementary species, they can provide a more stable and durable cover.  This doesn’t just happen.

This is a Rubus calcynoides, a durable, vigorous, ground cover, but it would be much more effective as a weed suppressor with a shrub and canopy layer. Geranium lucidum, an aggressive weed, is upper right. Problematic weeds in this bed include: Common Groundsel, Small Leaf Vetch, Dutch White Clover, Poa annua, Dandelion, Yellow Flowered Oxalis, Prostrate Knotweed, Creeping Bentgrass and Perennial Ryegrass. Like most Parks here this one is understaffed with horticulturally knowledgable staff. The horticulturist had just spent the previous 2 hours in the bed hand weeding trying to get rid of the flowering weeds before they could go to seed. There were several hours worth of weeding work left. The same person is responsible for many other parks in southwest which demonstrates an inadequate staffing level and will, inevitably lead to the failure of landscapes, no matter who that person is. Landscapes must be adequately maintained.

This large bed, around 3,000 sq.ft. arcs around the west side of a berm that backs the large central lawn at Caruthers Park in SW Portland. This was originally all Kinnickinnick, but became so overwhelmed with weeds that it was removed and replaced by this single species sweep of Rubus calcynoides which grows more densely and is more resistant to light foot traffic. The lawn is heavily used by area dogs and kids with the expected spillover.

People occasionally ask about native ground covers that they could substitute for their lawns and other parts of their landscape.  The same people are often asking for a low maintenance alternative.  Remember that native status does not translate into some kind of automatic survival superiority.  Only the most aggressive plants are capable of doing this.  Kinnickinnick is often planted in broad swathes with little else in it.  In my experience, most of these plantings can be quickly invaded by weeds.  It doesn’t create a weed suppressing mass of growth.  In nature it occurs as a component of a mixed plant community without the presence of the highly successful and aggressive eurasian weeds that are virtually everywhere in urbanized landscapes.  It is also intolerant of even relatively minor foot traffic being crushed by it…note the many trails through plantings of this on campuses and in Parks in the region.  Western Sword Ferns, Vancouveria, Achlys, Mahonia repens, Asarum, low growing Lupines and many, many, more, are wonderful members of our native plant communities, but we can’t expect them to thrive or even survive in landscapes where their requirements aren’t met.  Most of these when planted today are done so in a simple matrix, not generally on their own, but they are still far from a ‘silver bullet’ and must be accompanied by other natives appropriate to the site and not subjected to typical ‘urban pressures’.

For active spaces, like those that exist around many of our homes, schools and public spaces our choices must possess the durability to survive the use that they’ll receive.  If we aren’t willing or able to maintain healthy grass turf for these then we should consider other surface treatments be they gravel, concrete, asphalt, pavers, stone or the new generation ‘sports turfs’.  While these surfaces may not be ‘good’ for the wider environment, they at least recognize the reality of urban life and the pressures it puts on the landscape.  As I argued before we aren’t doing the wider landscape any ‘favors’ by growing weedy, poorly, performing landscapes.  These will only put more weed pressure on every other landscape.  Other, irresponsible practices, are hopefully being left in the past, e.g., pouring waste petroleum products on the ground or using old building materials like synthetic carpeting and composition roofing to either sterilize the soil or smother growth for longer term.

Hypericum calcynium was once widely used in this area by agencies on street area landscapes like road medians, strips and islands. Very often these were planted without irrigation. Very few or none of these are around anymore. This planting at one of my neighbors, on a west facing bank, has dead spots and contains a variety of weeds including Vetch, Blackberry and Trees of Heaven. Even a ‘good’ ground cover, when grown under stress, lacks the vigor of its competitors or has no allelopathic capacity, can fail.

What resources do you have that you are willing to commit?

We have to be committed to the care of all of our urban landscapes…it is a necessity!  All of our ‘built’ landscapes are contrived whether they are thoughtfully and intelligently designed or not.  They didn’t ‘evolve’ over millennia in your back yard, at the college campus or the park along the river.  They were built to meet a client’s expectation or our own.  The plant’s in them may have a cursory and very brief relationship with each other and the site.  When ‘disturbed’ these landscapes tend to move more out of balance.  They have neither the flexibility, resilience or integrity that a natural system would have and so lack their stability and balance that would move them back to ‘normal’ after having been disturbed.  A ‘native’ landscape, and for this I mean an undisturbed landscape that has developed prior to the land’s occupation by european Americans with our distinct pattern of disruption and development, is still dynamic.  It is able to ‘respond’ to more minor disruptions, perturbations, in a way that returns it to the original pattern.  In cases of relatively large disruptions like large scale hotter fires, that burn away at least part of the seed in the soil seed bank, a recognizable recovery, will still occur, provided there hasn’t been an introduction of exotic species.  In the later case it would likely take multiple generations for a new balanced landscape to grow on site as the many species ‘sorted’ themselves out.  Even so, in this later scenario, available species would colonize where they could, leaving many niches unfilled, the entire site remaining out of balance, because those capable of covering the soil, may do so only weakly leaving it ‘open’ or susceptible to other better suited species if and when they should move in.  Plant species are limited in their ability to move.  The further away a species grows the less likely it can occupy these available niches.  Seed must be physically moved to new sites.  Nature adds ‘new’ species to a landscape at a very slow rate, not like we do with our very mobile population and world trade.

These relationships between species have been ‘worked out’ in a native plant community on a particular site.  They grow in an adaptable matrix of possibilities.  Individuals fail or succeed on their own.  When we choose plants we presume to ‘know’ something about their ‘fitness’ for the site and how they may grow in relationship to all of the other members within the community, within the matrix.  If, however, we have simply chosen them because we want them or they serve our narrowly defined desires, we will have to intervene if they are to continue growing and do so to the degree that they are ill fitted.  When we plant a grass lawn, a bed of ground cover or any landscape for that matter, we are imposing our intention upon the site.  The ‘simpler’ the composition the more formal, rigid, its layout, the less capable our planting will be of continuing on and the more ‘disturbing’ our intervention, maintenance, will have to be to assure its continuation.  We need to understand that the work that is need is not simple ‘dumb’ labor.  People need to understand plants, their interactions and how their actions will influence them.

Landscapes can be rated on an intensity of maintenance scale.  Ironically it is often the most simple landscapes that pose the greater threat to the wider landscape because of the owner’s lack of commitment to actually maintain them.  The human factor is often the greatest variable.  Simplicity, in terms of plant diversity and the ‘formality’ of the design are important factors in that the simpler a planting scheme and more formal its layout, the more energy will be required to keep it in such a state.  In modern contrived landscapes this does not automatically translate directly into labor hours, because the use of various pesticides/herbicides will reduce the amount of labor hours as will the use of powered equipment.  For example pre-emergent herbicides and soil sterilants are commonly used, where legally permitted, to limit weed germination and growth at relatively little out of pocket cost and less labor.  They are used because they are very effective.  They are also highly disruptive in terms of the function of a healthy plant community.  A high quality grass lawn generally requires the use of gas powered equipment, the addition of fertilizers and occasional use of selective herbicides, in addition to its irrigation, but it requires less of the staff in terms of specific knowledge because it is such a simple system.  Over more recent years there has been a strong movement away from chemical intervention which is making the care of these simplistic landscapes more difficult especially if there is not the monitoring and labor commitment to adequately maintain them.  Problems are obvious.

A more complex landscape will require regular and frequent monitoring and timely and sensitive intervention, grooming and ‘editing’ to maintain it.  The use of herbicides can be problematic in these.  They require more knowledgeable and experienced gardeners and a greater time investment.  Simplistic planting schemes, provided the plants are well suited to the site, will be easier, in terms of complexity, to monitor and potentially, to maintain.  This presents an interesting dilemma, simple landscapes are ‘easier’ to monitor and maintain, but because of this they are ‘attractive’ to owners with little interest in caring for them, often resulting in highly degraded landscapes.  Complex landscapes are attractive to more interested and motivated gardeners and, because of this, present less of a threat to the broader general landscape, if they are maintained.  Of course, any landscape, no matter how well designed and maintained can decline rapidly when this commitment is lost.  Weed problems, because of the nature of  seed production, germination and growth  can cause an exponential rate of deterioration.  Simple landscapes like grass lawns can create a greater threat because they are so often allowed to deteriorate.  There is something very seductive to many people about a landscape that has been promised to them to be no or low care.

This is the ‘bowl, at GTM Waterfront Park, the site of events like the Dragon Boat Races and the annual Blues Festival. This shot, taken Sept. 7, ’17 shows the ‘recovering’ lawn. The thinness of the lawn is evident as is the surface erosion that occurs washing soil down slope into and across the ‘armored turf’ path at the edge, to the right, above the river.  I’ve often wondered if the geese who regularly graze this site are a factor in the Poa annua’s dominance here. ‘Cutting’ a grass shorter than it can tolerate, like Lolium perenne, weakens it and encourages dominance by other species.

Can I bring it back?

Resurrection of your lawn is as impossible as it is for any organism once it dies.  Your lawn has not gone ‘dormant’.  It will not ‘wake up’ in Spring or magically when you begin watering, unless the Perennial Rye that composed it, is still alive.  Repeatedly denying something essential to any organism will cause its death…not make it ‘tired’ and ‘go to ‘sleep’!  Winter dormancy for cold adapted plants is part of their normal cycle.  Tropical plants, plants not adapted to the severity of cold temperatures your garden receives, die.  They don’t go dormant either.  The plants that colonize your dead or dying lawn are adapted to your practices on the property.  The conditions under which your lawn has been growing/struggling will select from the available plants and seeds those plants best adapted to survive them.  This is natural selection in operation over the short term under highly disturbed conditions.  When you return to good cultural practices, what is there will respond with vigor…weeds and all!  What may remain of your Perennial Rye will respond…in conflict with the weedy species, and the selection process will respond to the change of conditions and component species.  This, again, is the issue with any plant community…change the conditions or the component plants and the plant community will change over time.  The forces of selection will do this.

If you want to ‘bring your lawn back’ you must change the conditions and the plant community.  This can take considerable effort.  You can either lay healthy sod down on top or reseed with an appropriate grass seed blend.  Grass seed blend?  In an attempt to toughen your lawn, grass seed growers have selected different varieties of the same species with slightly different characteristics.  Their goal is to produce a lawn that performs well across even incrementally different conditions so that its quality and performance can be maintained over a longer period of time.  Keep in mind that the grass seed you have spread will be competing with all of the weed seed that has accumulated over time on and in your soil.

In this closeup, again in the ‘bowl’, you can see that the turf grass is actually the weedy Poa annua, with its little ‘boat shaped tips at the end of each blade. This forms a very short and shallow rooted turf. It is common throughout Parks often occurring on compacted sites. After the summer events this area was mostly bare soil that was top seeded with Lolium perenne.

Because of the seed already in and on your site your are going to have to limit and control its germination and growth.  You’ll need to do this by ‘depleting’ the viable seed already their or preventing its germination over the longer term.  One strategy is to germinate and grow the weed seed there now, before you spread your desirable lawn seed, following up with an herbicide spray to kill the growing seedlings, thus depleting the available weed seed and improving the purity, quality, of your lawn to follow.  Keep in mind that doing this once will only ‘reduce’ the amount of weed seed available to germinate, not eliminate it.  Do this again.  This is highly recommended seeding a new lawn.

[You could also try ‘solarization’, covering the soil with clear plastic sheeting to raise soil temperatures to the point of sterilization for a long enough period.  This requires adequate soil moisture before you begin which helps cook the seed and other microbial in the soil.  Check the details of this before you attempt it.]

This may be even more necessary if you are attempting to seed or plant a meadow as a meadow ‘relies’ on its soil seed bank to regularly replenish itself, adding its own seed to it each year.  Meadows are natural systems.  Lawns are our own creations and are dependent upon us for their ‘replenishment’.

There is little to no Perennial Rye Grass in this picture or anywhere else in the ‘bowl’. Poa annua dominates and has for some time. The soil seed bank is filled with it. The stressful conditions work against the Rye and favor this Poa. A similar situation exists throughout much of this Park. Use and cultural practice favors Poa. Poa annua thrives under short frequent irrigation practice, which is the rule here under much of the summer because overseeding occurs after major events to revitalize over stressed Rye grass turf.  The frequent water schedule is also a result of the very dry soil that has resulted from the events, as staff tries to get soil moisture levels back up to where they need to be.  To water  too much too quickly results in more runoff and erosion.  The germinating Rye needs frequent irrigation which also favors the Poa. The short statured Poa annua reaches flowering height quickly producing seed well before and ‘below’ whatever Lolium perenne is around.  So why not yield to the Poa?  It produces a turf that is not as durable in terms of wear and it is very weedy…you will find it absolutely everywhere in and around the landscape.

Second, and this is less a strategy than an imperative and a caution, weed seed will be at various depths in your soil.  If you cultivate or disturb its surface, you will bring up previously buried seed.  Seed responds to temperature, moisture, even light.  The amount of weed seed is directly related to how long weeds have been actively growing and adding seed to the soil seed bank.  The seed of each species will germinate under conditions that it prefers.  If you disturb the soil, seed that was previously unable to germinate because of its depth, will now be able to do so.  Bear in mind that seed can remain viable for years, even in the soil.  If you till or regrade, limit this to your initial preparation!

A word on herbicide use: if your are going to grow a grass lawn you must keep in mind that it is a human invention, an extreme simplification, that is very out of balance with natural processes.  Weeds will invade it.  Modern landscapes have been so thoroughly penetrated by exotic weed species that it must be assumed that they are everywhere.  Weeds are a ‘response’ to the modern human way of life.  We disturb and we spread.  Wishing them away or ignoring them will always fail us and the landscapes that they put under threat.  We have two choices, to scrupulously follow the best cultural practices for each of our landscapes including the regular monitoring of weeds and pests, responding quickly to the appearance of ‘threats’ by manually removing/controlling them, as well as the necessary irrigation mowing, aerating, pruning, mulching, clean up and ‘editing’ necessary to maintain their health.  This would include adjusting our uses of the land in ways that support their healthy growth, and, the ‘responsible’ use of herbicide.  Notice that I did not say the routine use of herbicide.  Using it as a routine, scheduled, practice is an indicator of either ‘bad’, insufficient cultural practice and/or a landscape that is inappropriate given the conditions on site and the commitment to its maintenance.  Idealism won’t get us where we need to be…nor can we abdicate our responsibility and excuse our ignorance.  Ultimately we are responsible whether we reject it our not.  Fault matters little to the dead and failed landscapes.

Whatever you choose to do with your degraded and droughted lawn, a well designed and maintained landscape will put less pressure on surrounding landscapes.  A landscape that is better suited to the conditions on its site will always require less maintenance.  A site with a long history of neglect will contain more weed seeds that can germinate reinfecting your site if you aren’t vigilant.  If neighboring landscapes provide an ongoing source of weed infection in your landscape you will always have to work to stay on top of your weed problem…and, this will always be the case in urban landscapes.  Those who argue in favor of Nature’s ability to heal itself are forgetting that we are a ‘rogue’ element of nature and that as long as we are taking actions that continue to disturb the site, we will be perpetuating the imbalance and preventing a new one from being reached.  Even if we were able to remain neutral in terms of our disruption, it would take many generations to reach such a new ‘state’.  We must learn to better integrate our actions, harmoniously and intelligently, with what is happening in our landscape.

As a concluding note I’ve often found it interesting that people east of the Cascades, on the dry side of the state, often are much more active participants in the care of their grass lawns.  In Bend and Redmond, where I grew up, most people seemed to water and mow throughout the short summer season producing green lawns and watching them go ‘cold dormant’ over the long winter months.  While on trips to the ‘Valley’ we would commonly see brown, droughted, lawns through  the summer and green one’s over the wet winter months.  I used to find that curious.  After having lived here for some time I came to realize that over mild years, homeowners here could conceivably mow on any given month of the year and, by the time summer came around, many had tired of doing so.  So far most people here keep their ‘lawns’ rather than convert them to a more neutral or productive landscape.  Willamette Valley residents have found other reasons to justify this choice, saving on their water bills and being green, being chief among them…only, as I’ve pointed out earlier, this practice is not a responsible one regarding the health of the wider landscape.