GARDENER'S READING ROOM
The Art of Gardening
Trees & Shrubs

Gardening beneath Trees

Large trees are valuable in many ways as part of our landscapes. They offer many seasons of enjoyment from interesting bark to fragrant flowers to autumn color. Trees can represent history: A tree planted lovingly on Father’s Day later offers sturdy branches to climb upon, and then perhaps shades a grandfather relaxing on his favorite bench. Many trees offer food to us and to wildlife. Trees also decrease air pollution and slow the flow of rain water into storm drains. Large trees can increase property value as part of the landscape. So, how does a gardener plant wisely beneath these large trees?

• Plant small starts 4-8 feet away from the trunk of the tree, allowing plants to gradually grow closer to the trunk.
• Surface irrigation is the ideal way to water plantings around trees. Adjust sprinklers to keep the tree trunk dry and free from disease.
• Mulch beneath large trees with wood chips to a 3” depth, at least 3-4 feet away from tree trunk. Avoid using compost as it contains too much nitrogen.
• Leaves are nature’s mulch and are extremely beneficial to healthy tree development, so let your leaves lie to create the perfect mulch in the fall.
• Avoid using weed barriers at the base of trees because barriers prevent the movement of organisms and recycling of nutrients into the soil.
• Avoid using lawn fertilizer around tree roots. Their high nitrogen content can be detrimental to trees. Weed and feed products are even worse.
• If you are constructing something near established trees, avoid tree root damage by creating a buffer with wood chips spread to 6” deep over the site to absorb some of the impact. When construction is complete thin wood chips even with tree roots.
• The “Achilles heel” of a growing tree is located where the tree trunk flares at the base to meet the roots. Please keep this area uncovered to support the tree.
• When cultivating beneath large trees, plant bulbs which naturalize well.
• Beneath deciduous trees, plant herbaceous perennials which can handle leaf fall.

Some plants that will grow nicely with your large trees are: salal, sword fern, Oregon grape, epimedium, vancouveria, vinca, deer fern, tolmiea, fringe cup, some perennial geraniums, fragaria, crocus, daffodils, snowdrops, checkered lilies, oxalis, rubus pentalobus, dicentra, maianthemum, hellebores, sarcoccoca, leucothoe, and cyclamen.

With these tips now you can carefully cultivate around that living legacy, great giant, tree treasure in your landscape.

By Kristel Dillon
Skylights Summer 2008, Vol 23, No. 2

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