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Steele: Managing the fallout from fast-growing elm trees

Part of their toughness is due to their drought-proof, deep taproot.
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This Siberian elm seedling, growing between sidewalk and a rock wall, already had a taproot longer than the four inches of top growth. It is essential to recognize the seedlings and remove them immediately. -Image: Gwen Steele

Every year our city’s large population of Siberian/Russian elm trees creates a ‘snowfall’ in late May when mature seeds blow into gardens and every nook and cranny.

These large shade trees are tough and fast-growing, likely the reason so many were planted in earlier days.

Part of their toughness is due to their drought-proof, deep taproot. It enables them to grow in dry, natural landscapes as well as irrigated gardens.

Each tree produces ‘millions’ of flat, dime-sized, off-white seeds which germinate readily.

It’s common to Siberian elms growing in awkward places—inside hedges, in cracks in sidewalks, against the foundation of a house—as well as flower beds. Siberian elms can grow more than five feet a year.

The taproot grows as fast, or faster than the top, making it difficult to dig out even when young. If any root is left in the ground it will re-sprout. A good way to get rid of a larger tree is to girdle it between late spring and mid-summer. This involves removing a section of the outer layer of bark around the circumference of the trunk thus depriving the tree of nutrients. It should cause death in one to two years. Once dead, it can be cut down. Cutting down a live tree does not kill it. It re-grows from the roots.

Other drought-tolerant tree seedlings to watch out for and remove quickly are Tree of Heaven (easily recognized by the stinky smell of leaves and branches when rubbed) and Russian olive. These and the elm are considered invasive.

In our irrigated landscapes, maple seeds germinate well and can grow quickly in the same difficult places the other tree seedlings populate.

If you have squirrels in the neighbourhood, as I now do, you may find walnut, oak or hazelnut seedlings in your garden beds.

Images on the internet are helpful to identify any of these tree seedlings. Dig them out as soon as spotted to avoid future difficult or costly removal.

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The annual launch of the Make Water Work contest was held at the unH2O Garden last week.

Valley mayors took the pledge to reduce their landscape water use and to enter the competition to see which municipality can get the most (per capita) pledges.

Go to www.makewaterwork.ca/pledge to pledge to reduce water use in your yard and be entered to win one of three $500 prizes.

The City of Kelowna and OXA, are sponsoring ‘Homeowners Irrigation and Landscaping Information Session’, Saturday, May 26 from noon to 4 p.m. at the Kinsmen Field House, 3975 Gordon Drive. RSVP to watersmart@kelowna.ca for this free presentation.

The Kelowna ‘Flower Power’ Garden Tour is Saturday, June 16. Early bird tickets are still available. Check www.flowerpowerylw.ca/ for details.

This year OXA will have an information booth, on the tour, in a xeriscape garden in the Hall Road area.

Gwen Steele is executive-director of the non-profit Okanagan Xeriscape Association. Learn more about Gardening with Nature and plants for the Okanagan on the website at www.okanaganxeriscape.org