Marianne Binetti

Food, water, pruning keep flowers going into fall

Now is time to give your potted plants extra attention if you want to enjoy beautiful blooms into the fall season. By the middle of August, the roots of geraniums, petunias and verbena have grown enough to fill up containers of potting soil, so your potted plants will need more water and another dose of fertilizer to keep them in blooming good shape. Continue to deadhead or remove the faded blossoms to encourage more blooms.

Here are more tips for keeping specific flowers producing until the first fall frost:


Keep soil constantly moist and fertilize with a balanced plant food, such as Peter’s Professional, that has all three numbers on the fertilizer label equal such as a 20-20-20 mix. Fuchsia baskets are heavy feeders and create flowers on new growth, and so lots of nitrogen helps to encourage more foliage that will deliver more flowers. Fuchsias hate hot weather, so if your hanging baskets have suffered in the heat, you can give them a fresh start by cutting back the dangling branches by one-third and watering well. Place your basket in a well-shaded location and water twice daily if the temperature goes above 85 degrees. Deadhead fuchsias by removing not just the faded bloom but the swollen berry or seed pod behind the faded flower as well.


These heat-lovers will thrive in sunny locations but they must have well-drained soil. When you deadhead geraniums, be sure to remove the stems as well as the blossoms and collect any yellow leaves from the base of the plants. Geraniums do well with a slow release plant food, such as Osmocote, and many gardeners claim that their geraniums produce the most blooms when the plants are slightly stressed — either root bound in a pot that looks too small or allowed to dry out between watering. If your geraniums produce huge leaves but few blooms, it might be due to a plant food that is too high in nitrogen or soil that is too rich in compost. The first number on a fertilizer label denotes nitrogen and this should be smaller than the second and third number for most flowering annuals. A classic plant food for geraniums and other bedding plants would be labeled 5-10-10.


The biggest complaint about potted petunias is that they imitate Vegas show girls and become leggy. Once you see blooms on only the tips of the branches, it is time to get snippy and cut back your petunia plants by at least one-third. Daring and confident gardeners will cut back petunias this month by one-half. This extreme makeover will leave petunias without any flowers for a few weeks but the new growth will be full of flower buds and you’ll enjoy bushy and beautiful plants until October — but only if you feed and water your petunias immediately after the haircut.


There is still time to renew and refresh your disappointing container gardens if you visit a garden center or nursery and look for some late summer or early autumn color. Don’t focus on just plants with flowers. You can fill your pots with leafy cabbage, fleshy succulents or spiky grasses and enjoy the coming fall season without the guilt of looking at miserable plants that you forgot to water. The best weather for outdoor living in Western Washington is often the month of September, so an investment in beautiful plants during August will pay lovely returns on your energy investment.

Marianne Binetti has a degree in horticulture from Washington State University and is the author of several books. Reach her at