Weather in early June is still spring-like in the Pacific Northwest. It is an ideal time to continue planting. Sometimes June planted tomatoes and other warm weather vegetables catch up and surpass those planted earlier in cooler weather. Now is the best time to prune spring flowering shrubs and to remove those water sprouts on trees.
SHOULD I PICK UP LAWN CLIPPINGS?
There is a continuing debate about whether it is better to pick up grass clippings or let them remain on the lawn. The biggest advantage to letting clippings fall between the grass blades is that they add nutrients to the soil. In a year’s time, lawn clippings will add enough nutrients to be the equivalent of a full fertilization. However, if the grass is not mowed frequently, blades are long and may accumulate on top. If the grass is wet when mowed, clippings may clump together. Mulching lawn mowers do a better job of chopping clippings into fine pieces so they filter through the blades easier. Another advantage of leaving clippings is the time saved in emptying the clipping bag and disposing of them.
The biggest reason to pick up clippings is that they can be tracked into the house. However, no lawn mower is 100% efficient in throwing clippings into the bag. The 10 to 30% of clippings left on the lawn can still be tracked in.
If you do pick up clippings, use them as much as possible for compost or mulch. They can be applied almost everywhere you would use bark or other mulch. Clippings dry to a light tan color, and are not as attractive as dark brown bark. However, they are great around vegetables, fruit trees and berries. They break down into humus more quickly than bark and add nutrients to the soil.
LAWN LOSING ITS COLOR?
If you plan to irrigate your lawn this summer to keep it green, now is a good time to apply a slow release lawn fertilizer. Check the label to see if at least part of the nitrogen is either insoluble or poly coated.
REMOVE SPROUTS ON RECENTLY PRUNED TREES NOW
June is a critical time to remove those fast growing vertical sprouts that occur after trees are pruned in the fall, winter, or early spring. This is particularly true for fruit trees which have been heavily thinned so light can reach the lower fruiting branches. Sprouts can be quickly and easily snapped off with your fingers when they are soft and flexible. Snapping is preferable to cutting, because it removes tissue which can regrow another water sprout, sometimes in the same growing season. If you wait until fall or winter to remove those sprouts, new ones will grow to replace them next spring. Stop the sprout cycle now. And if you do happen to have more new water sprouts later, snap them off while they are young and soft.
If you also have large woody water sprouts from previous years, now is a good time to remove them too.
PRUNE SPRING FLOWERING SHRUBS
The ideal time to prune flowering shrubs such as Rhododendrons is soon after they have bloomed. This is the time when shrubs can be shaped or shortened without affecting next year’s bloom. We have about two months to prune before new flower buds are formed for next spring. It is not necessary to prune flowering shrubs if you are happy with their shape and size. However, if they have overgrown sidewalks or windows, now is the best time to prune. Most shrubs also develop some dead wood as older branches are shaded by new growth. If it is hidden inside where you can’t see it, don’t worry about it. If it is affecting the beauty of the plant, remove it now.
Do not shear shrubs with power clippers unless you want them to look like hedges. You will create artificially dense growth and unnatural shape. Make individual cuts to keep a natural shape and thickness. One of my services is to teach gardeners how to prune their own shrubs and trees using natural pruning techniques. Or I can do the pruning for you.
MULCHES REDUCE WEED GROWTH AND IMPROVE PLANT GROWTH
Nothing makes a flower or shrub bed look neat and attractive like a fresh application of mulch. In the Pacific Northwest, bulk bark dust is readily available and inexpensive. If you don’t have access to a pickup, it can be delivered to your driveway. If you don’t have time to spread it yourself, we can do it for you.
Most weed seeds need light to germinate. Mulch prevents most light from reaching the soil surface. So weed growth is greatly reduced. Weed preventing chemicals can also be applied before or after applying mulch to further reduce weed germination. Soil can also be covered with weed barrier fabric before applying mulch.
Mulch also reduces water evaporation which reduces the amount of water needed for summer irrigation. Organic mulches such as bark dust and compost add nutrients to the soil as they break down into humus. They also improve the physical structure of the soil which improves water movement into the soil and plant growth.
KEEPING ROSES DISEASE FREE
I have recently seen powdery mildew on new growth of some roses. It takes regular spraying to prevent powdery mildew on susceptible varieties. I try to spray at least once every two weeks.
As weather warms we will see black spots on older leaves and rust spots on leaves of certain varieties. Removing old yellow leaves with black spots prevents them from inoculating new growth.
My favorite pesticide for rose diseases in Neem Oil. This is a natural extract from the neem tree. If sprayed weekly it will prevent all 3 rose diseases from developing. As a bonus, it also kills aphids and other insects which attack roses.
Most pesticides protect new growth but do not affect already damaged leaves. Systemic fungicides stop disease development within the leaf. Check ingredient labels of disease control products to find one of the following systemic fungicides: tebuconazole, propiconizole, thiophanate methyl and triforine.
DISEASE RESISTANT ROSE VARIETIES
Many disease resistant rose varieties are now available which do not require frequent pesticide application. I googled “disease resistant roses” and came up with lists from Oregon State University and several other sources. Knockout, Floral Carpet, and Kordes Vigorosa are 3 new series of disease resistant roses.