August Gardening Checklist: Essential Tasks For A Healthy Late Summer Garden

August can be one of the toughest months in the garden. The heat is still intense, rainfall can be unpredictable, and many plants begin looking tired after months of blooming. But don’t put your gardening gloves away just yet. A little attention now will reward you with healthier plants, fresh blooms, and a beautiful garden well into fall.

This month is all about maintenance, preparing for the changing season, and getting a head start on your fall garden. Here’s everything I focus on in my own August garden.

August Garden To-Do List

Instead of focusing on adding lots of new plants, this month is about taking care of everything that’s been growing since spring.

1. Give Summer Perennials a Mid-Season Refresh

This week, I spent several hours giving my garden a much-needed refresh. I cut back my salvia after its first flush of blooms and pruned my catmint and lavender, both of which were beginning to look a little tired. These perennials usually reward a midsummer trim with fresh foliage and another round of flowers that will carry the garden beautifully into early fall.

2. Weed Before They Go to Seed

August weeds seem to grow overnight. So I pulled and sprayed for weeds throughout my flower beds before they had a chance to set seed. It isn’t the most exciting garden task, but staying on top of weeds now saves so much work later.

After weeding, I noticed a few areas where my mulch had thinned over the summer. I added a fresh layer to those sparse spots to help retain moisture, keep the soil cooler during the August heat, and discourage new weeds from sprouting. Besides the practical benefits, fresh mulch instantly makes the entire garden look neat and well cared for.

3. Water Deeply, Not Daily

Once everything was pruned and mulched, I gave the beds a deep watering to help the plants recover from the heat and encourage healthy new growth. Rather than watering every day, aim for fewer but deeper waterings.

Most established plants do better with about 1 inch of water per week, either from rainfall or irrigation. Water early in the morning whenever possible to reduce evaporation and help prevent fungal diseases.

Pay extra attention to:

• Newly planted shrubs and trees
• Hanging baskets
• Containers and window boxes
• Hydrangeas
• Vegetable gardens

Containers often need watering every day during August heat.

4. Deadhead Flowers for Continuous Blooms

Removing faded flowers encourages many annuals and perennials to keep blooming. Continue deadheading:

• Coneflowers
• Shasta Daisies
• Black-eyed Susans
• Zinnias
• Cosmos
• Petunias
• Geraniums
• Coreopsis
• Roses
• Day lilies
• Hostas

Not only does this keep the garden looking tidy, but it helps plants direct energy into producing more flowers instead of seeds.

5. Give Hydrangeas a Little Extra Attention

By August, hydrangeas are often feeling the effects of summer heat. Large leaves lose moisture quickly, and the plants can look wilted on hot afternoons, even when the soil is adequately moist. They should perk back up by evening or next morning, that’s perfectly normal. If not, then they need more water.

Water deeply once or twice a week during dry spells rather than giving them a light sprinkle every day. A fresh 2- to 3-inch layer of mulch around the base helps keep the roots cool and conserves moisture during the hottest weeks of summer.

Resist the urge to prune most hydrangeas in August. Many varieties, including bigleaf (mophead and lacecap) and oakleaf hydrangeas, are already forming next year’s flower buds. Pruning now could mean fewer blooms next summer. Instead, simply remove any dead, damaged, or diseased stems and enjoy the flowers as they age.

If you’re growing panicle hydrangeas (such as ‘Limelight’ or ‘Little Lime’) or smooth hydrangeas (such as ‘Annabelle’), save major pruning until late winter or early spring before new growth begins.

One of my favorite things about hydrangeas in August is watching their flowers change color. Depending on the variety, blooms may fade into beautiful shades of soft green, dusty pink, burgundy, or antique cream, adding just as much interest to the garden as their peak summer color.

6. Feed Container Plants

Plants growing in containers quickly use up available nutrients. Continue feeding flowering containers every couple of weeks with a balanced liquid fertilizer through August to keep them blooming until frost. Garden beds generally don’t require heavy fertilizing this late in the season.

7. Harvest Often

Your vegetable garden should be producing heavily now. Harvest regularly to encourage continued production. Don’t let oversized vegetables remain on the plant—they slow down future production. August favorites inlcude:

• Tomatoes
• Cucumbers
• Zucchini
• Peppers
• Green beans
• Herbs

8. A Healthy Garden Starts with Regular Walks

One of the best habits you can develop is simply walking through your garden every few days. Look under leaves, inspect new growth, and check flowers closely. Most pest and disease problems are much easier to manage when caught early, often requiring nothing more than hand removal or a quick rinse with the hose instead of stronger treatments later.

Late summer does bring increased insect activity. Keep an eye out for:

• Japanese beetles– These metallic green and bronze beetles feed on flowers and leaves, leaving behind a distinctive lace-like skeleton. The easiest method is to hand-pick beetles early in the morning when they’re sluggish and drop them into a bucket of soapy water. Avoid placing beetle traps close to your garden, as they often attract even more beetles to the area. Keeping your garden clean and removing damaged foliage can also reduce feeding.
• Tomato hornworms – These large green caterpillars can strip a tomato plant of its leaves almost overnight. Inspect tomato plants every few days, especially underneath leaves and along stems. If you spot a hornworm, simply remove it by hand and relocate or dispose of it. If you notice white rice-like cocoons attached to a hornworm, leave it alone—those are the cocoons of beneficial parasitic wasps that naturally help control future hornworm populations.
• Aphids – Clusters of tiny green, black, yellow, or white insects often gather on new growth and flower buds. For small infestations, spray them off with a strong stream of water from the garden hose. You can also remove heavily infested stems or wipe leaves with your fingers. If the problem continues, insecticidal soap or neem oil can help when used according to the product directions. Ladybugs and lacewings are also natural predators that help keep aphid populations under control.
• Spider mites – Spider mites thrive during hot, dry weather and can leave leaves looking speckled, bronzed, or covered with fine webbing. Increase humidity around affected plants by watering the soil consistently and occasionally rinsing the undersides of leaves with water. Remove badly damaged foliage. Insecticidal soap or horticultural oil may help if populations become severe.
• Powdery mildew – Powdery mildew appears as a white, dusty coating on leaves and is common during warm days with cool nights. Remove affected leaves if the infection is light and avoid watering foliage overhead. Water at the base of plants early in the day and improve air circulation by thinning crowded growth when appropriate. If needed, use a fungicide labeled for powdery mildew and follow the manufacturer’s directions carefully.

9. Start Your Fall Garden

I’m also beginning to think ahead to fall. I’m planning what vegetables I’d like to grow in my containers. August is actually the beginning of the fall gardening season. Depending on your growing zone, you can begin planting:

• Lettuce
• Spinach
• Kale
• Swiss chard
• Arugula
• Radishes
• Beets
• Turnips
• Carrots

These crops often perform even better in the cooler temperatures of autumn than they do in spring.

10. Think Ahead to Spring

August is a great time to begin planning for spring bulbs. I’m deciding where I’ll tuck in spring-flowering bulbs later this season, and making notes about areas of the garden that could use a little more color next year, what struggled this year, empty spaces, and new plants I want to add.

Living Layered Tip – Take photos of your garden while everything is still growing. It’s much easier to remember where bulbs, perennials, and shrubs are located before everything dies back in winter. Your future self will thank you!

11. Support Heavy Plants

As vegetables mature, tomatoes, peppers, and dahlias may need additional support. Tie stems loosely to stakes or cages to prevent breakage from storms or heavy fruit.

12. Skip Heavy Pruning on Shrubs

Avoid major pruning on spring-flowering shrubs. Pruning now removes next year’s flower buds. Save major shaping for after they bloom next spring. Do not to prune shrubs that are already forming next year’s flower buds, including:

• Hydrangeas (bigleaf, lacecap, and oakleaf)
• Lilacs
• Azaleas
• Rhododendrons
• Forsythia
• Weigela
• Viburnum (most spring-blooming varieties)

Instead, simply remove dead, broken, or diseased branches and wait until the proper pruning season.

Looking Ahead

August is less about planting something new and more about caring for everything you’ve already grown. It’s amazing how just a few hours of maintenance can completely refresh a garden, and keep it looking beautiful well into September and October, while setting the stage for an even better garden next year.

Continue Your Gardening Journey

If you’re looking for more seasonal gardening inspiration, be sure to read these related articles:

• The Complete Guide to Preserving Your Garden Harvest
• How to Attract Butterflies to Your Garden
• DIY: Outdoor Water Fountain

What are you working on in your garden this August? I’d love to hear what you’re growing and how you’re preparing for the upcoming fall season.