Agapanthus for the Maritime Pacific Northwest: Not all of these are well suited for us…or are they?

A fellow gardener asked the question about whether there were a list of sure thing Agapanthus, plants that a beginner could confidently choose and have success with in most of the maritime PNW.  I’m going to say no.  All of these are South African natives and while many of us can grow these in our gardens, because our conditions overall are marginal, a gardener is going to have to possess a good understanding of their site in particular and some knowledge of the cultivars that they are choosing.  I’m going to borrow here from Manning and Goldblatt’s book, “The Color Encyclopedia of Cape Bulbs”, which discusses the bulbs of the Cape Floristic region and those adjacent areas spilling over into other parts of South Africa. Agapanthus species are native there, endemic in fact, occurring naturally no where else in the world.  I’m also relying here on the SANBI website, the South African Natural Biodiversity Institute which has put together an incredible national program, which all countries should be building for their own countries.  Being a South African plant aficionado I visit it frequently. To this I add my own observations and speculations, having grown several Agapanthus over the last 25+ years in Portland: These come from warm temperate and subtropical areas in South Africa, 10 species total, 3 limited to the Cape itself, all of which tend to occur in rocky grasslands.  Other botanists have downgraded 3 of Manning and Goldblatt’s species and given them subspecies status recognizing only 7 species.

All Agapanthus are limited to areas where the rainfall is more than 20” annually, ranging across areas from sea level to 7000 ft, with a distribution range that extends from the Cape Peninsula in the far south-west, along the southern and eastern coast of southern Africa then inland and northwards into the mountainous regions south of the Limpopo River, an arc which makes up part of South Africa’s boundary with Zimbabwe.

The four, more tender, evergreen species are found in the far south portion of the continent and along the rocky coastline where the rain falls predominantly in winter, or intermittently throughout the year in the more eastern portion of this range, the influence of two different oceans with their weather patterns.

None of the species grow in the hot, arid interior. The other species, all deciduous, grow in the northern portion where they stretch up along the far eastern portion of South Africa which has a pronounced winter drought.

Goldblatt and Manning write that which ever species you try, keep the crowns dry, use a gravel mulch.

To improve as a gardener we must dedicate some of our energy to understanding the heritage of the plants we grow. This is always important, especially so for plants whose performance may be considered marginal in our area. There is no reason why a beginner cannot grow these here…if they understand that they will have the most consistent success growing them in pots which they protect from winter freezing.  If we’re going to grow them in the ground we must be more careful.

Choose plants from the 7 other deciduous species, or hybrids of these to get plants most tolerant of our conditions and then experiment.  ‘Storm Cloud’ was my first acquisition.  More  than a few people told me they would just die, it didn’t, although I lost it a few years later when I moved it to a less sunny spot.  I smiled and told them that that was fine with me. I was experimenting and while I was doing that they were buying the same or similar annuals every year with no expectation that they would return, so…..The health and vigor of any plant is a result of their genetics and the combination of the conditions under which they live.  Minimum temperature varies with the other conditions.  Every individual, every species has the capacity to adapt, but only so far.  Marginal conditions will compromise the health and vigor of any organisms.  Cold can kill your Agapanthus, especially if it is compromised by its climate, soil organisms, the ripening which results from summer heat…and others.  How different are the garden conditions you offer your plants from the conditions these evolved with in their native sites?

Headbourne Hybrids are relatively common in the trade here. The labels of these typically claim cold hardiness.  I have not knowingly grown any of these. Their parentage is mixed. Agapanthus campanulatus var. patens is a smaller deciduous agapanthus with deep blue flowers from the higher elevations (5,900 to 7,900 feet) in the Drakensberg Mountains of South Africa, in the eastern portion of the country. As an eastern range you should understand that this region receives summer rainfall. This species has long been used for hybridization with other species, adding its smaller size, hardiness and deep blue flower color to the genetic mix. It was a primary parent of the well-known Headbourne Hybrids that were bred in England by Lewis Palmer in the late 1940’s at Headbourne Worthy and introduced in the 1950’s and 1960’s.  It would be best to think of this group as a ‘family’ of hybrid crosses, utilizing different species and varieties, crosses and back crosses. Because of their mixed lineages, there will be variation in their hardiness.

Agapanthus cross freely on their own and there are many named hybrids and selections though most are not available in large numbers and have limited distribution. Even when records are scrupulously kept, some of these crosses will involve unknown pollen donors.  Other breeders may be casual and ‘blood lines’ are lost.  Because of this it is highly unlikely that we will ever know the lineages of all of the plants in our gardens and sold from nurseries.  Doing DNA analysis is still relatively cost prohibitive.  This then means that we should pay even more attention to the individual performances of the cultivars available to us so that we can pass on such knowledge.  Because of their morphological similarities it is difficult to discern the lineages of any Agapanthus by comparing them morphologically, by their appearance.  

We rely largely on appearance to link or separate one plant from another, to see the shared physical patterns amongst organisms which link them together.  For many centuries we have depended on our eyes and the physical cues we see to define species and then to link those in larger related groups, genera, families and on.  This helped us tell the story of their evolution and gave us hints as we looked at their commonalities and considered how to grow them.  Of course now we are beginning to rely much more on a species’ genetics to make these connections, because the phenomenon of convergent evolution, the tendency of plants to follow particular structural patterns, though their genetic links are far apart, gives us doubt to the limits of our eyes and what we see.  When botanists work to define a species the plants don’t present themselves clearly, they vary across a range.  Often, even within a single genus, like Agapanthus, the physical differences between species are quite small and the untrained person can have a great deal of trouble separating out one species from another.  When you throw in hybrids, it becomes nigh impossible.

For many gardeners, most novices, the finer differences in appearance are lost.  They/we see mostly the shared characteristic form of the plant, its tuft of strappy grass like leaves out of which the tall narrow flowering stems stretch holding its ‘ball like explosion’ of flowers aloft.  Each possess the relatively long, soft, softly channeled leaves with rounded tips and the trumpet like, 6 tepaled flowers, though they will likely see them as petals, in shades from white to deepest blue.  When they see them growing in others gardens, in magazine spreads or offered by their local garden centers, the novice will tend to think the only thing to do is plant them in their garden and success will follow.  They won’t understand what may be required to have that success or that their expectations, given their own gardens conditions, and their own understanding and limited practice, may be setting them up for failure.  They may read the label or they may simple assume that because it is offered it will grow for them where they choose to plant it,  Until they are ‘bitten’ by the gardening bug, they will be frustrated by this…afterwards, their failures will either draw them into the gardening world, or convince them that their ‘thumbs are brown’.

The Northwest’s adopted horticultural son, Dan Hinkley, has long loved Agapanthus and has collected and made some of his own selections which he’s tested in his own Puget Sound gardens. If you have ever had the opportunity to visit his garden on one of his open days in mid-late summer, you will be astounded by the display of Agapanthus he has planted out. He has offered, in very limited numbers, some of his proven favorites. What needs to happen is a more concerted testing program of the plants he has been growing and then the participation of other small regional nurseries committed to increasing these and offering them to the public. Until then we’ll just have to keep an eye open and be ready for the occasional gift a garden friend may have to offer us. Click this link to go to Dan’s web page to see his list of Agapanthus, but understand that you will have to be patient to acquire any of them. With your own success perhaps you can then later pass on the wealth.

Species:

africanus True A. africanus, is limited to a small area in the mountains along the coast of the Cape province, with their deep blue flowers. A. walshii, (walshii has been subsumed into africanus) with its nodding flowers, are two other evergreen, southern species that won’t work here so avoid them as well, unless you are going to commit to caring for them with a greenhouse over winter and pay particular attention to their water requirements. These must be kept dry in the summer. These are intolerant of freezing so will freeze and/or rot here consistently in the ground over our winters. These two species also have been found to bloom best in habitat after having been burned over!

Agapanthus campanulatus This species and its subspecies are usually smaller deciduous plants growing in colonies occurring in moist peaty soil at low elevations in the Drakensburg Mountains across the region’s extensive grasslands in rocky places, often amongst bracken, and in moist peaty soil at low elevations on moist slopes and in valley bottoms, drainage lines, on cliffs and slopes up to 2400 m in the Eastern Cape, Lesotho, KwaZulu-Natal, Gauteng and Mpumalanga.   Agapanthus campanulatus subsps. campanulatus is found at lower elevations in the midlands of KwaZulu-Natal and in the Eastern Cape and the Free State. It ranges across Natal and the North Cape province. SANBI

A. caulescens. These plants are deciduous and occur in summer rainfall areas where the temperature sometimes drops below zero degrees Celsius in winter and where it may snow. In the winter rainfall region of South Africa plants go dormant and are unaffected by the winter rains if they have a well drained site. SANBI

A. coddii  This species comes from the Waterberg, a summer rainfall region, in the Limpopo Province (former western Transvaal). It grows in montane grassland, usually in permanently moist seepage below cliffs.

A. inapertus  Agapanthus inapertus occurs through Mpumalanga, Swaziland, northern KwaZulu-Natal, Gauteng and the Northern Province, all summer rainfall regions. It often occurs in mountainous, rocky areas and is common along the Drakensberg Escarpment.  This species has proven to be one of the most dependable in PNW gardens. Its inflorescences have dark blue to purple flowers on drooping pedicels. SANBI

Agapanthus praecox, the largest of the evergreen species. It is native to the winter rainfall Western Cape and the all-year rainfall Eastern Cape with several subspecies populating these different sub areas. This area is not an area subject to any kind of significant freezing so you can’t expect these plants to possess a lot of freeze tolerance. This species is one of the most commonly grown perennials in the world, its ease of cultivation and rapid multiplication lend itself to this. In recent years A. comptonii has been absorbed into praecox as a subspecies.  In the northern hemisphere these have sometimes been mislabeled as A. africanus, a species little used in horticulture and poorly adapted to our condition in the PNW anyway. Its vigor probably contributes to its being used in many hybrids. Ease of cultivation and multiplication would go to explaining this species and its hybrids propensity to escape and dominate in warmer climates. Growing A. praecox and its hybrids in cooler temperate/maritime climates like the PNW, a marginal area for these, will result in spotty performance. While these may be a ‘no brainer’ in central and southern California, we are different enough here that average/baseline conditions will be problematic. A. praecox will require summer moisture in dry summer regions to perform well. Those selections and hybrids from eastern subspecies will tolerate some moisture throughout the year. On the surface this would seem to make it a good ‘garden’ plant for us, however, we are cooler and wetter, with our rain falling primarily over our fall, winter and spring seasons, heaviest in winter. As we often have heavier, clay. loam soils, which hold water, our soils can foster a variety of deleterious rot organisms. A. praecox, and by extension much of its hybrid progeny, would best be grown in pots throughout the maritime PNW and brought inside during the freezing portion of our winters. A. praecox may be successfully used in hybrids for warmer climates than ours, but it can also lead to a tenderness. We will have a greater success if we attempt to grow species from Agapanthus’ northern range and higher elevations or select hybrids that depend less on A. praecox and A. africanus. SANBI

I would not include Agapanthus on a list of beginner plants for gardeners in the PNW unless they were restricted to use in pots, pots that could be protected over freezing periods.  Such a ‘list’ will vary from region to region, require that they ‘fit’ with the prevailing conditions in your region and on your site.  Such lists often only include plants that are consistently cold hardy across USDA zones one or two below one’s on local range.  While assuring success, such a practice both limits the gardener significantly in terms of choice and can lead them to ignore  the particulars of their sites and the particular requirements of plants they might choose.  As gardeners we seem to need to confront failure in order to learn…which is not very surprising.  What may be difficult on one site may be simple on another.  This holds true whether you are considering Agapanthus, Agave, Abies or any other plant. 

Many plants can be difficult even in situations where most of the physical conditions are supportive, but one element can be off enough to create disaster for that species.  Summer humidity can do this causing one plant to all to disease when it wouldn’t under lower humidity levels; a rain regime that’s in conflict falling heavily when a plant has no need can cause problems with soil aeration; a soil difference can effect aeration, pH and nutrient levels: a particular pest or disease common in a garden’s location can attack a plant with inadequate resistance, any of these and more can compromise plant health and make it that much more susceptible to cold and a host of other factors.  It is difficult to say what may torpedo the efforts of even an accomplished gardener when they attempt a plant outside of their experience.  Every success and failure offers us lessons if we are aware.  In my case I have lost far too many woodland species having been slow to learn that just because my overall climate is supportive and that I may have the right amount of shade, each plant may have some critical element missing in my garden like soil organic content, a duff layer, even though I add compost.  The compost ‘burns’ away faster than I can replenish it, my resultant soil to heavy for these plants to survive our cool wet winters.  Mine is not a woodland garden.  Whatever the plant we choose, it has evolved within a range of conditions, conditions which themselves are in a particular relationship forming a linked system.  Conditions are not independent. When one is limited it shifts the balance of the whole as they are a coherent, related, network or system. When summers are on the cool side, when winter soils are wet, the soil biome is radically different, an unfamiliar, poorly adapted plant can be easily compromised and be less tolerant of what we have to offer it.  If, however, our soil has quicker drainage characteristics in terms of its structure and texture, then there will be more Agapanthus that we can grow, climatic conditions being the same.  We need to know our site.

Whichever Agapanthus you attempt to grow pick a site with full sun to provide the energy they need over the growing season to develop and ‘ripen’.  Plant them in well drained soil.  In habitat almost everyone of these grow in rocky soils, which will tend to drain faster than those without rock.  Our soils are all much more subject to saturation because of the volume of rain we can receive in winter months.  Moist is good.  Saturated is bad.  So drainage here is even more important than it is in South Africa.  My garden has Latourelle Loam soil, soil that you can’t find a rock in, the relatively rich, high in clay content, is wonderful for warm season vegetable gardens and many of the tropical/subtropical plants I choose to grow.  My soil type fills the lower elevations of the Willamette Valley and need drainage ‘help’ to grow Agapanthus, and many other plants, successfully and well.  Without amendments my soil dries in summer forming large cracks, an indicator of its clay content.  A south sloping site would help as would raised beds which from which water can drain away from the root crown.  Evergreen trees can draw a lot of water away in the winter.  A tree’s roots extend well beyond their canopy’s drip line, plant them where they get full sun and the benefit of the tree’s ‘thirsty’ roots.  Plant them with neighbors with the same requirements.  If you choose to amend to improve the drainage, do it for the entire bed, amending for a single plant can backfire resulting in the ‘tea cup’ effect, the water in the surrounding unamended soil draining back into the amended soil rotting roots.  And, consider watering these periodically over summer as many come from regions with year around rainfall and all of them tend to occur only where 20″+ falls annually.  Yes, we get well more than that, but our summer months are remarkably dry, so supplement.

Some of the Agapanthus I’ve grown:

‘Blue Triumphator’ I think this is the one I got at the last Seattle Study Weekend, from Dan Hinkley’s offerings, I lost the label before I recorded it.  This one has survived the last two winters in my garden, but isn’t happy. I need to find a better spot or consign it to a pot.  Award of Merit from the Royal Society.

‘Ed Carmen’ a larger growing form with creamy gold leaf margins.  Lost this in its first winter of ’15. Soil was likely too heavy and it was in too much shade. This large white flowered form was selected by Sean Hogan of Cistus Nursery and named after the San Jose plantsman.  It has proven hardy down into zn8a for others.

‘Hinag’ syn. ‘Summer Gold’ This was a beautiful, more compact growing, plant with yellow variegated margins.  It didn’t bloom for me in the pots I used it in, but I didn’t care.  Much more attractive as a ‘filler’ than the commonly used Liriope mascari ‘Silvery Sunproof’. Sadly another plant I lost frozen in its pot one winter when i didn’t get it protected.  Plants with a zn8a rating, may survive 10ºF when established in the ground, but may succumb in pots, especially if they are smaller….

Agapanthus inapertus subsp. pendulus ‘Graskop’ I’m a little embarrassed about this one, allegedly one of the hardiest available, I killed it in the ground, again in heavy soil with about half day sun….beautiful plant.  Deciduous this comes from the grasslands around the Drakensburg Mountains and north.  This subsp. is native to Mpumalanga province near the town of Graskop.  SANBI

‘Peter Pan’ a dwarf, lt. blue flowered plant.  My oldest plant I’ve had it in the ground for over 15 years.  I moved it to a sunnier spot a couple years ago as it was getting increasingly shady in its old location.  The flowering has more than tripled after the move.

‘Phantom’ A beautiful acquisition from Dan Hinkley two years ago, we both love this plant with its long flower stems and large white trumpets flushed with pale sky blue.  This has been a good performer for me, increasing a bit in my small South African section, though it needs more sun, a problem with an increasing portion of my main garden. From the National Agapanthus Collection in Devon, England.

x ‘Storm Cloud’ is my first Agapanthus.  I grew it successfully in Parks display beds, at home in the ground and in pots. Said to be hardy to zn7a I eventually lost mine when I moved it to the east side of my house where it probably got too much shade…it also got a lot less summer water….This is a winter deciduous plant with beautiful dark blue flowers. A seedling from the open pollinated parent, ‘Mood Indigo’.

‘Tinker Bell’ a variegated sport of Peter Pan with beautiful foliage, but did not ever flower for me. I grew this in a pot and lost it one winter when it was left out and the pot froze hard.

General information on South African Biomes

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