Monthly Archives: February 2025

On Ornamental Trees and the Remaking/Unmaking of Place: Revising the City of Redmond’s Tree List, part 2

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How Much to Water?

Recommending trees from climates with significantly wetter growing seasons needs to stop if we are to continue growing our population. Landscapes as designed, and managed, are the single largest user of residential water. Recommending trees which ignore this problem is irresponsible. Lower water use residential landscapes are possible. Local codes and recommendations must, however, reflect this priority.

Additionally, how much to water is a bit of a mystery to all of us and especially so to non-gardeners. How much? How often? Our watering practices should be determined by the local precipitation and the tree’s needs. What is commonly done, however, is that we water for our lawns and that largely determines what our trees receive, unless we have separate drip systems. A tree’s root system doesn’t stay neatly between the lines. They quickly extend out well beyond the span of the tree’s leafy canopy. In many cases even 2-3 times as far, taking up water and nutrients. A roots of a tree, planted in a small bed, adjacent to an irrigated lawn area, will move out into the lawn. A tree isolated in a xeric bed with only a few drip emitters, will quickly demand more than such a meager system affords it and such a tree, if it requires summer moisture, will struggle while competing with its nearby  ground level growing neighbors. Again ‘neighbors’ should share compatible requirements so all can thrive on the same ‘diet’ and moisture regime. Continue reading →

On Ornamental Trees and the Remaking/Unmaking of Place: Revising the City of Redmond’s Tree List, Part 1

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Perhaps an odd tree to start this with, Juniperus scopulorum ‘Woodward’, is not a ‘shade tree’. It is not deciduous. It is a narrow, fastigiate form of Rocky Mtn. Juniper that, growing to a height of 20′ with a 2′-3′ spread can serve as a formal accent in colder climates like ours as a ‘replacement’ for the more tender Italian Cyperss, and it can do quite well here with very little supplemental water.

Trees, specifically ornamental shade trees, have become an expected and desired part of our urban lives, at least util their leaves fall and await our cleanup. Many associate long tree lined streets and avenues with urban living. Broad Maples. Lofty Elms. Plane Trees and, in tighter spaces, perhaps Cherrys, Crabapples and flowering Plums. Urban trees provide several notable ‘environmental services’ increasing our comfort level with their cooling shade, their capacity to remove pollutants from the air, cover and nesting places for birds and the sequestration of carbon. Trees are generally viewed as a public good, necessary even for our lives. We can get quite emotional about them. So it seems a bit ‘wrong’ to suggest that this ‘ideal’ may not always be ‘best’ or even desirable.

Broadleaved deciduous shade trees are ‘naturally’ members of mesic, temperate to cold-temperate regions of the world. That is where they evolved and where when we plant them out, where they do best. When we begin planting them outside of their historic natural ranges, especially when we ignore the conditions, the disparities and the extremes between their natural ranges and those where we choose to plant them, then we can have some serious problems. The trees may struggle along, or if we remain committed to making up for our local area’s lacking, usually in the form of supplying more water, they can do reasonably well. But this suggests possible real problems as one moves further away from the conditions of a tree’s natural limits and increase the numbers planted out. Where is this water coming from and what are the impacts of removing this water from its normal and healthy cycling of which it is a part? What will be going without? And, is that cost worth the losses it creates? Our selection and planting decisions depend on how we value that which is lost! In short, the typical deciduous shade tree of our imaginings does not belong here in a desert. Continue reading →