This guide is tailored for the western valleys of Oregon and Washington.
Readers’ suggestions are requested. Also please note that 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! —Nathan
YOU can help to make the world a better, a more friendly, loving and beautiful place by being a good steward of of spot on this earth that you are borrowing for a time—your garden. Nathan, the Treevangelist, urges you to treat it like your own personal Garden of Eden paradise. Then notice the joy that it will bring to you! Here is a to do list to help you to do just that…
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.
- Hedges: Shear after spring growth and before hot weather. Shearing during hot weather may result in sun scald of foliage.
- 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 us.
- 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.
- Ornamental shrub pruning: 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.
- Pine tree pruning: Don’t do major pruning of pine trees during the growing season, since this attracts sequoia pitch moth infestation.
- 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.
- Prune fast growing ornamental shrubs 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.
- Rhododendrons: Remove old blooms (called “dead heading”). Though it looks better aesthetically to remove the dead blooms, it doesn’t hurt the plants to leave them on.
- 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
Good News Tree Service, Inc. provides full plant health care services as listed below.
- Aphids: If aphids are a problem, there are a variety of ways to effectively control this pesky insect that drops its sticky honeydew excrement all over vehicles and hard surfaces. Ask Good News Tree Service, Inc. for solutions to your aphid problems.
- Arborvitae Twig Blight: Spray in the spring and early summer when new growth starts at two week intervals.
- Bronze Birch Borer: Treat any time this month. If your birch trees are dying, it is likely because of this pest. Treatments are available and effective , but expensive. Trees can be effectively treated from mid-May through June.
- Dogwood Anthracnose: If you missed spring foliar spraying, can use treat with a systemic fungicidal basal bark spray (available through a licensed commercial pesticide applicator). Symptoms of this foliar fungal disease include brownish, reddish purplish leaf spots getting increasingly larger as the summer draws on until many leaves are no longer predominantly green.
- Deep Root Fertilization: Trees and ornamental shrubs—deep root fertilize to promote lush, healthy-looking and vigorous crown growth. Urban soils tend to lacking in many of the nutrients that trees and shrubs need to survive. Many are malnourished or are starving to death, which is why they don’t look radiantly healthy are struggling with pest issues. Deep root fertilization helps to promote healthy-looking and pest-resistant trees and shrubs. The best time of the year to do this is in the spring and fall.
- Lawns: Fertilize lawns.
- 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.
- Tent Caterpillar: Apply systemic pesticide for season-long control.
- Verticillium Wilt: You can still treat trees for this soil born fungal pathogen during the summer, but 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.
- Continue planting annual and perennial flowers.
- 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.
- 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.
- Fertilize your ornamental shrubs with a slow release fertilizer. If the shrubs have a layer of barkdust or other mulch around them, rake the mulch away and apply the fertilize to the bare dirt, so that it actually reaches the plant’s root zone.