This guide is tailored for the western valleys of Oregon and Washington.
YOU can help to make the world a better, a more friendly, loving and beautiful place by being a good steward of the spot on this earth that you are privileged to be borrowing for a time—your garden. Nathan, the Treevangelist, urges you to treat your spot on this planet like your own personal Garden of Eden paradise. Then notice the joy that it will bring to you! This is your Divinely mandated responsibility. Your trees, shrubs, flowers and the wildlife in your yard will express their smiling appreciation back to you as they radiate love , joy and beauty bursting forth with vibrant and verdant life. Here is a to do list to help you to do just that…
Readers’ suggestions on how to improve this list are gladly solicited. If you, the reader, have any suggestions for additions to this month’s list, please put them in the comments section of this article, and I will add them to the list. Thank you in advance! — Nathan
August in the garden can be a quiet time due to the hot weather. Trees, shrubs and lawns begin to go into their summer dormancy (conserve energy and to withstand the stress of hot weather) and either quit growing or slow down. This is a good time to step back and to enjoy your garden and do a little relaxing yourself. You can always catch up on weed pulling—they seem to keep growing anytime. The main thing to remember is to water, water and water your trees and shrubs that need it. Most well established, deeply rooted trees and shrubs need little or no water. But many of your smaller plants with shallower roots, and especially your flowers will need constant watering. How can you tell if your larger trees and shrubs need water? They’ll tell you. When their leaves begin to wilt, they need some water.
Tree and Shrub Care
- Birch trees: Thanks to the bronze birch borer beetle, a large number of the Pacific Northwest birch trees are dying. To make your tree less hospitable to this nasty and lethal pest, there are two inexpensive things you can do. First, apply several inches of mulch to the ground under the canopy of your birch tree. Second, with a whirly bird sprinkler, irrigate the area under the birch’s canopy. The more water the better, since birches are water-loving trees. Irrigate once a week for several hours during warm weather and twice during hot weather. These two actions will lessen the chances that the beetle will attack and kill your birches. The bronze birch borer beetle can be treated in the late spring, but treatments are expensive. Call GNTS. Inc. for more info.
- Dogwood trees: Monitor leaves for signs of anthracnose. As the summer draws on, the symptoms on the leaves get worse. (See more info below.)
- Maples (including Japanese maples): Monitor the leaves of all maples and other trees and shrubs for symptoms of the potentially lethal verticillium wilt fungal disease. If you see branch dieback, call GNTS, inc..
- Mulch: Apply two to three inches of mulch around all trees and ornamental shrubs. This helps to fertilize the plants and feed the soil, and also protects them against weed growth and loss of water when the warmer weather returns.
- Pruning of trees and shrubs: You can do all aesthetic pruning of all ornamental shrubs and trees (except pines) at any time of the year including summer. Don’t over-prune the top crowns of thin barked trees (e.g. Japanese maples, flowering cherries), since the sun’s UV rays can cause trunk and branch bark dessication resulting in cracking and dieback of sapwood and even heartwood resulting in entry points for diseases and potential structural failure of branches and trunks.
- Be careful not to do major pruning during periods of hot weather, since doing so exposes tender leaves underneath that haven’t acclimated to the sun’s ultraviolet rays yet, since they have been shielded by the layer of leaves you’ve just removed by pruning. Sun scald of these tender leaves may occur, especially on southern and southwestern sides of the plant. Sun scalded leaves won’t kill the plant, but it looks unsightly and diminishes the plant’s ability to photosynthate (produce food for itself).
- Pruning of large trees: Most trees in the temperate western valleys of Oregon and Washington can be pruned anytime of the year. If you’re not sure what to do, or how to do it, call Good News Tree Service, Inc. for a consultation, pruning lessons or to have them do the pruning for you. It is likely best to wait for cooler weather to prune stressed or sick looking trees. Call us if you have questions about this.
- Prune fast growing ornamental shrubs (e.g. laurel, privet, photinia, laurustinus, barberry) that are beginning to look shabby. You may need to prune them again in the early summer for a more neat and manicured look.
- Tree and shrub removal and stump grinding can be done all year long.
- Trees: Have an ISA Certified Arborist with an ISA Tree Risk Assessment Qualification (like Good News Tree Service, Inc.) inspect your large trees for the potential of failure due to weak root systems and defects in trunks and branches. This can be done anytime of the year.
- Watering: During the hot summer months, well established trees and larger ornamental shrubs need little or no watering. However, newly planted trees and shrubs will need watering for the first two to three summers until their roots get established. Regular lawn irrigation isn’t sufficient to give trees and shrubs the deep watering they need to survive the summer heat. During warm weather, deep water your new plants at least once per week. During hot weather, twice per week.
Plant Health Care
- Deep Root Fertilization: Don’t do so after the weather becomes too hot. Fertilizer will push out new growth, which will likely scorch in sun. This is a waste of fertilizer and plant resources.
- Dogwood Anthracnose: If you missed the spring sprays topical fungal sprays, and you see signs of anthracnose on your tree’s leaves (reddish, purplish, brownish splotches), you can spray your trees with a basal bark fungicide. Call GNTS, Inc. for information on this treatment.
- Monitor trees and shrubs for insect pests: Piercing and sucking plant pests (e.g. aphids, lacebugs, scales, weevils, mites, etc.) are now out and active. If major infestation occurs, plan a course of action to treat your trees and shrubs against these pests. Small numbers of piercing and sucking insects are not harmful to plants. In fact, they provide food for the beneficial, predatory insects that feed on them. To control harmful insects, one can apply systemic insecticides against piercing sucking insects (aphids, lacebugs, scales, weevils, etc.) via soil injections (one treatment gives season-long control). If applied according to label directions, this will kill only the harmful and not beneficial insects.
- Spider mites will start to become active as the weather warms. Systemic insecticides are available against this pest.
- Verticillium Wilt: The fall is the best time to treat, and spring is the second best time. Maples are especially plagued by this disease. During hot weather, symptoms include smaller than normal cupped leaves in the upper canopy, often with the death of the entire branch occurring.
Elsewhere in the Garden
- Put slug bait around your flowers and tender perennials like hostas.
- Apply two to three inches of mulch (e.g. bark dust, garden compost or wood chips) on all of your shrub beds. Covering bare dirt areas in your yard with mulch helps to prevent soil compaction from rains, and weed growth, and helps to enrich our heavy clay soils.
- Cut English ivy off of the base of trees. (This can be done any time of the year.)
- Feed the birds. Dutifully maintain your bird feeders. Bring life and excitement to your backyard by turning it into a bird sanctuary. The birds will thank you for your generosity by providing you with hours of entertainment, and by eating insect pests that harm your ornamental trees and shrubs. Birds in the yard are not only fun to watch, but they perform the vital task of eating harmful insects. Keep bird baths full. In hot and dry weather, birds need water to drink and to bathe in.
- This is a good time of the year to plant trees and shrubs. Visit your local nursery and select your favorite ornamental shrubs and shade trees. After planting your new shrubs, just make sure that you water them well immediately and regularly subsequently for the first two or three summers until their roots get established. During warm weather (in the 60s to low 80s), deep root water once per week. During hot weather (mid-80s and higher) deep root water at least twice per week.
- Water and fertilize annuals and perennial flowers. The hotter the weather, the more water they will need. Flowers in pots and hanging baskets dry out especially quickly, and so need watering every day or two.