August brings small jobs and manageable projects in our gardens. It is a month to tidy up from summer, prepare for fall and even plan for next spring. With that in mind, here are some tips and reminders to take you through the mix.
Prune off dead and declining foliage from plants that are still producing. Browning leaves can not only harbor insects and disease but they are unattractive.
Remove annuals and crops that have stopped producing; they provide shelter for insects and disease producing organisms.
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Clean up fallen rose petals and leaves to help prevent the soil from harboring fungus diseases.
Control weeds before they go to seed. They produce thousands of seeds that will germinate in your and your neighbors’ yards.
Self-seeders, usually annuals and biennials, include alyssum, amaranthus, calendula, chives, columbine, coneflowers, cornflowers, cosmos, foxglove and sunflowers, among others.
Leave the seed heads on the plants to spread as they will or remove the seed heads and lay them on the ground where you want them to grow next year. (Be aware that the birds will eat many of the seeds.) Make a note where they are in garden or mark them with stakes so you don’t mistake sprouts for weeds in the spring. Don’t depend on your memory. It seems like such a simple detail now but their location will be lost in mulch, weeds, fallen leaves, pine needles and other debris come spring.
Planting and transplanting
Perk up flower beds through fall with coleus, begonias, marigolds, New Guinea impatiens, cosmos, various salvias and other seasonally colorful plants.
Sow biennial hollyhock and foxglove seeds in August and September for blooms in spring 2016.
Divide iris in August. That is when they have stored enough food in their rhizomes to re-establish in a new spot.
Buy the biggest and best spring blooming bulbs for superior flowers in 2016. Do it in August because availability drops off in the fall. Err toward too many rather than too few bulbs in case some don’t sprout. Also, follow the recommended number to plant per square foot. Hold them in a cool dry place until November or December for planting.
Order bulbs for forcing and pre-chilling. Many spring blooming bulbs need a 12- to 14-week chilling below 45 degrees Farenheit. Plan ahead.
Some spring-blooming bulbs don’t require chilling. Check the hardiness zones for allium varieties before you buy; some are good in Zone 8, others are not. The same is true for anemones. Crinum lilies, Gloriosa lilies, paper whites, daffodils and spider lilies do not need chilling. Snowflakes (Leucojums) do better in our heat than Snowdrops (Galanthus).
As flowers fade, prune summer flowering shrubs if necessary.
Sheer evergreen hedges for the last time this year. Sheer too late and you’ll stimulate new growth that will be vulnerable to frost.
August is the last month to fertilize your warm season grass (centipede, St. Augustine, zoysia and Bermuda) this year – after August no fertilizer, no weed and feed product, no winterizer product.
Plants should be well watered before you fertilize; avoid application when it is hot and the soil is dry. Without enough water the salts in fertilizer will burn a plant.
Don’t fertilize woody plants; it will stimulate new growth which may not have time to harden off before the first frost.
Watch for fall webworms on trees. Open up the webs with a hard spray from a hose or a long stick so birds and wasps can feast on the caterpillars.
Apply Bt (Bacillus thuringiensis) to protect vulnerable crops and ornamentals from chewing caterpillars.
Spider mites are damaging and multiply quickly. Control them on arborvitae, juniper, rosemary, oregano, thyme, verbena and other plants with horticultural oil spray.
Continue to treat aphids on new growth. Hose them off or spray with insecticidal soap.
Scale is an ongoing problem, especially on evergreen ornamentals. Spray with horticultural oil. Treatment requires multiple spray applications.
Stay vigilant for lace bugs on azaleas. Spray with acephate, a foliar systemic.
With any pesticides, always read the label and follow instructions for use.
Reach Debbie Menchek, a Clemson Master Gardener, at email@example.com.