Best Horticultural Tips for August
Trees & Shrubs
- Now is the time to select and plant bulbs for spring blooming.
- Bone meal is a recommended fertilizer when planting bulbs in the fall.
- Clematis: If it is blooming now it probably is a group 3 pruning variety. These varieties bloom on current years growth. Prune in early spring when buds begin to swell.
- Japanese beetle life cycle: Both larva and adults are destructive pests. Adults emerge in June and July, lay eggs, which hatch, and the larva exist in the soil until next June/July by feeding on roots of turf and some perennials. Putting down grub control in late June to early July will help control newly hatched larvae, but not the adult beetles emerging from the soil. A product like Scott’s GrubEx, which contains imidaclopid, has the added benefit of not harming bees if part of the application goes into a garden. And if you have a garden close to a Linden tree or any other tree the beetles feed on, treating the garden area is a good idea.
- Adults feed on leaves of at least 300 different species. While it is understandable that some gardeners will vent their frustration by squishing the beetles, this is the wrong approach. The pheromones released will only attract more beetles. The best approach is to go out with a bucket of soapy water in early evening, pluck the little buggers off whatever they are eating, and throw them in the soapy water where they will drown.
- Japanese beetles will not eat the following flowers:
--Coral bells, coreopsis, delphinium, foxglove, hosta, impatiens, lantana
Japanese beetles will feast on
--clematis, dahlia, hibiscus, holly hock, Japanese maple, Linden tree, roses, sunflower, butterfly bushes.
- Some homeowners report insecticidal soap stuns Japanese beetles on contact. There is no evidence that this, extract of garlic, hot pepper or orange peels will be effective. Organic spays like Neem Oil and Pyola will protect roses. DO NOT BUY JAPANESE BEETLE TRAPS. THEY WILL ACT AS A BEACON TO YOUR YARD!
- Cut back and fertilize annuals so that their display continues into fall.
- Take cuttings from geraniums and begonias for over-wintering indoors.
- Continue to water new perennials (as well as trees and shrubs) planted last spring by hand.
- Coneflowers have two parts: the petals (called rays) around the outside and the center cone. If deadheaded, flowers will continue to come. If left to stand, goldfinch will come feed on the seed heads. The plants now come in unusual colors. Try a new one!
- While it is a myth that you can tell the age of a ladybug by the number of spots it has, it is true that a ladybug can eat up to 50 aphids a day!
- You can help control cicada killer wasps by keeping the area they frequent wet.
- Pick cucumbers frequently, before they mature. If the seeds of even one fruit mature, the entire vine will stop producing.
- Plant grafted roses 1 ½ to 2” deeper than ground level in order to protect the bud union, the most tender part of the plant.
- Remove faded flowers from annuals for increased fall blooming.
- Fertilize flowers (not roses) for fall growth.
- Give your houseplants a bath to remove the dust.
- Plant vegetables for fall harvest.
- Yarrow: Cut back after it blooms.
- Goatsbeard is for the shade. Think astilbe on steroids.
- It is the time of year to seed or over-seed your lawn.
- Buying cheap seed often results in disappointment due to the weed seeds included in the mix. Read the package carefully to discover what percentage of the seed is not grass seed.
- If seeding a new area, cover lightly with topsoil or compost.
- In the Midwest, perennial broadleaf weeds are best controlled with postemergence herbicides in the fall (Sept. 1 to Nov. 15). Most herbicides work really well on a certain number or set of broadleaf weeds. But nothing works on every broadleaf weed. Read the label of the product purchased carefully to make sure you will get the coverage needed.
- August is a good time to over seed. Scratch the area to be reseeded so that the seed has contact with the soil. Keep the seed damp with daily watering for best results.
- Crabgrass can be sprayed now with Drive.
- Plan for the fall seeding or aeration of your lawn.
- If you have never soil tested your lawn, now is the time.
- Beautiful lawns are made in the fall, not the spring.
- The first step for successful lawn seeding is to buy quality seed. Cheap seed ends up being no bargain, for several reasons.
- Read the seed label and look for the percent of weed seed or other crop seed. The percent should be zero.
- The most important tip for lawn seeding success is to irrigate the seed frequently.
- For cool season lawns (what most people have here) tall fescue and Kentucky bluegrass should be the seed of choice
- Plan for the fall aeration and seeding of your lawn.
- Check for grub damage; they will be 1” below soil level.
- Mowing frequency should depend on growth rate of grass not the day of the week.
- Research has shown that a late fall application of fertilizer on turf is very important in cool season turf grass. Plan for that now.
Trees & Shrubs
- Know what you are doing before you attempt to prune a tree. Check the Extension Office guide to pruning. If in doubt, call a professional. Trees are an investment that add value to your property.
- Trees react to pruning because
-- it wounds the tree
-- food production is reduced
-- hormones are activated
-- it potentially alters the stability of the tree
- Rejuvenation pruning of shrubs (best done after their flowering period)
-- reduce to 6 to 10 inches above ground. Healthy shrubs will respond.
--or remove one-third of oldest (thickest) branches three years in a row. This method is less drastic and prevents the shrub from “disappearing” from the landscape during the recovery period. The shrub also stays more attractive. --Rose of Sharon shrubs can be pruned or thinned each year. Just remember they bloom on 2nd year’s growth.
- Check evergreen trees and shrubs of all types for spider mites. Shake a branch over a white piece of paper to see the tiny mites. Problems can be controlled with insecticidal soap (small area) or Bifenthrin for large shrubs or trees.
- A yard without shade can be 20 degrees hotter than one with shade. Fall is a great time to plant a tree.
- Warts on hackberry trees are galls. They are common, unsightly, but not harmful. Control is not necessary.
- Suckering is common in summer on some trees. Prune off—herbicides should not be applied as this may kill or damage tree.
- Healthy trees and shrubs are not killed by defoliation.