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Almanac: July – August 2019

Divide and replant bearded irises.

Pinch back chrysanthemums and asters to keep them shorter and bushier. Stake perennials that tend to flop.

Deadhead some perennials and annuals to keep them blooming, others to avoid self-sowing and the plant’s wasting energy on seed production. 

Cut back mounding perennials such as geraniums, pinks, alyssum, creeping phlox, and aubretia when they are finished blooming.

Cut reblooming roses back slightly.

Keep container plants watered and fertilized.

Water newly planted woody plants. Ten to 15 gallons of water is needed weekly when rainfall is less than one inch.

Plan how to protect woodies from deer.

Keep water gardens full.

Deadhead Japanese tree lilacs as much possible to encourage more bloom next year and prevent unwanted seedlings.

Mowing the lawn as high as possible results in a healthier lawn with deeper roots more tolerant of drought and denser turf—this will prevent germination of some weed seeds.

Start some perennials from seed, but plan on overwintering them in a cold frame. 

It’s finally okay to remove narcissus foliage. This is also a good time to move the bulbs, or you can dig them up and let them dry for planting in September.

Move colchicum in early July. If you forced bulbs last winter, remove them from the pots and store them dry and cool for the summer (except for delicate bulbs like snowdrops). Watch out for narcissus bulb fly!

Divide and replant bearded irises. Destroy old or rotten rhizomes or those with iris borers. Do this before Labor Day to allow sufficient time for rerooting.  

Tour private gardens and arboreta. Take your camera and notebook to record ideas.

Mark colors of phlox and daylilies in case you want to propagate and share them. Photograph your garden and make notes of needed changes.

Check viburnums for viburnum leaf beetle (VLB) adults, especially if the shrubs were defoliated by the larvae. Consider a pesticide treatment to save the shrubs. Do NOT cut back branches just because the leaves have been eaten or damaged. Scratch the bark with your fingernail. If it’s green underneath, the branch is alive. Dormant buds under the bark will eventually develop into sprouts and leaves. Snip off and destroy the twigs that contain the VLB eggs. Although the egg-laying sites are most obvious in the fall, one actually has until April to trim the affected twigs.  

This is the last month to fertilize woodies without encouraging tender late growth that may not harden off in time for winter. It’s also the last month to prune woodies—except for dead or diseased wood.

Early in July, emove peas and other early veggies and replace with either quick-growing veggies such as snap beans, cucumbers, summer squash, green onions, beets, kohlrabi, and radishes, or else cool-tolerant, slower-growing veggies such as carrots, broccoli, cauliflower, cabbage, collards, kale, peas, head and romaine lettuce, and parsley.

After August 1, only plantings of leaf lettuce, spinach, turnips, and radishes can be expected to produce a crop in a normal year in upstate New York—gardens in zone 6 near the lake have another week or two of growing season. Cover newly planted seeds with rowcover to keep them cooler and moist.

Renew the mulch in your veggie garden.  

Keep up with weeding! If you can’t remove all the weeds right away, at least don’t let them go to seed.

Cover blueberry plants with bird netting before birds discover the fruit. If it’s dry, water the plants well.  Use large buckets, with holes drilled in the bottom for slow deep watering and to measure how much you are applying. Before renewing the mulch, do a pH test. If the pH is higher than 5.5, consider broadcasting sulfur on the ground and watering it in before mulching. Your Extension office can advise you how much sulfur to apply based on pH.

Keep tomato branches inside their cages. Remove spotted or yellow leaves (put them in the trash). This will slow down early blight and septoria leaf blight. A layer of fresh mulch may help to interrupt fungus infection.

If you suspect late blight, take leaf samples or pictures to your local Extension office.

Continue to cut off curly garlic scapes as they appear to encourage larger bulbs. 

Pick raspberries every day, especially if the weather is wet or humid. If raspberries or other soft fruits look moist or misshapen, check for the maggots of the two-spotted drosophila fruit fly. Destroy all the bad fruit. If a lot of fruit has been set, you can then use rowcover to keep the fruit flies out, but this will also prevent further pollination. Also look out for the marmorated stink bug.

Keep your food plants weeded, watered, and mulched. Uneven watering may cause blossom end rot of tomatoes. Blueberry bushes are particularly sensitive to drought

Carefully guide melon and squash vines where you want them to go.

Renew or move the strawberry bed. Moving the plants now allows thorough weed removal and enough time to plant a succession crop (see above).

Keep the asparagus bed weeded. You shouldn’t be harvesting any longer. Watch for asparagus beetles.

Maximize basil harvest and prevent blooming by cutting plants back by one-third rather than just plucking leaves. 

Handpick Japanese beetles, Colorado potato beetles, etc. Look for the eggs on undersides of leaves. Use Bt insecticide on cabbage family plants, but remember Bt will also kill the caterpillars of desirable butterflies. Grow extra parsley, dill, or fennel to have more black swallowtails, and leave common milkweed in rough areas for monarch caterpillars.

If you have a lot of apples or crabapples, thinning the fruit may reduce the tendency to biennial bearing that might result.


Continue to water newly planted woodies (see July). Plant evergreens by mid-September in order to establish before winter.

In late August, plant corms of either colchicums or the true autumn crocus (Crocus speciosus, etc.) as soon as they are available.

Nursery stock goes on sale and may be a good moneysaver if it has been well cared for. Score the rootball of pot bound plants with vertical cuts to ensure root growth into the surrounding soil. If rain is insufficient, water weekly. Continue watering until the ground freezes.

In late August, preferably before the end of September, move and/or divide some of the hardier perennials, especially the spring-blooming ones.

Order bulbs for fall planting to get the best selection of varieties. Many spring-blooming bulbs are deer-resistant, such as allium, winter aconite, snowdrop, leucojum (snowflake), Siberian squill, glory-of-the-snow, puschkinia, fritillaria, and Anemone blanda. Grape hyacinths send up fall foliage, but even when it’s browsed that doesn’t seem to affect their vigor.

Keep the lawn mowed high, but if a drought drags on, allow it to go dormant (brown). It will revive when rains resume.

Late August and early September is the best time to renovate a lawn or to seed a new one. 

Start protecting tree trunks from “buck rub” damage.

Late in August, bring in poinsettia and Christmas cactus to get them adapted to indoor conditions. Start exposing them to long nights (short days) for flowerbuds to set. After checking for insects, bring in houseplants before nights cool off too much outside and heating systems start operating. 

In zone 5, August is the last month to plant early broccoli or cauliflower transplants, leaf lettuce, spinach, and turnip.  Protect them from the scorching sun with rowcover or milk crates.

Harvest garlic when the leaves are yellowing. Next you can weed the area and plant a late crop. Rotate garlic, so pick a new spot with lots of sun and good drainage. Sheet compost the new spot now, until planting time in mid-October.

Continue weeding, watering, and mulching as needed. Try not to get leaves wet to prevent spreading disease. Watch closely for tomato/potato late blight.

Keep harvesting beans, basil, okra, cukes, summer squash, eggplant, etc., for plants to keep producing. It’s okay to leave some peppers on the plant to ripen and turn color.

—Pat Curran and the Tompkins County Master Gardeners

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