I am discouraged by the appearance of my annuals growing in containers and a couple of beds. I was hoping they’d look better by this time of year. What can I do to bring back some more vibrant color this gardening season?
— Brett Caraway, Lincolnwood
I can relate to your frustration with some plants not performing as expected. There are several things in my home garden that I need to adjust to. Your experience with annuals growing in containers is not an unusual one. Plants grown in containers need to be watered routinely, especially during summer when the plants have grown and the weather gets hotter. Frequent watering leaches nutrients out of the growing medium in containers, so plants that show stunted growth, yellowing foliage or reduced flowering may just need to be fertilized. Rain can also leach nutrients out of containers. This could be the problem with the annuals in your containers. If you reused the growing medium from last year, this could also be a cause of reduced plant health. New soil mixes often have fertilizer in them that leaches out and is used up by the plants over the course of the growing season. Use a liquid fertilizer now to give the plants a boost. It is best to fertilize containers and baskets when the plants are moist. Fertilizing plants that are dry can result in damage to the plants’ roots. Repeat as needed to improve the plants; the frequency will depend on conditions in your garden, but once a month is a good place to start. I like to use a slow-release fertilizer when planting containers to gradually release nutrients over the course of the summer and reduce the need to use a liquid fertilizer. If your containers excessively dried out during one of the recent spells of hot weather, your annuals may have been damaged and may need some tender loving care to recover.
Be sure to use a growing medium designed for container gardening. Regular garden soil doesn’t work in a container because it doesn’t drain well, and plants will struggle as a result. Containers must have holes in the bottom for drainage. You do not need to put gravel at the bottom of containers for drainage, but holes in the bottom are very important. Plants will slowly die with yellowing foliage as water builds up in the container and drowns the roots.
The annuals that are not performing well in your garden beds may also benefit from liquid fertilizer, but first make sure you have chosen the right plants for your site’s growing conditions. Are those annuals well matched to the hours of sunlight your beds and containers receive? Plants that require (or prefer) full sun will not perform well in the shade; the more shade they are in, the worse these plants will perform. You may notice stunted growth, reduced flowering, or even nonexistent flowering. Even shade-loving plants can struggle if the shade is very deep. Overwatering can also result in stunted growth and off-color (yellow) foliage in annuals. Overwatering from an automatic sprinkling system could also be part of the problem. It is also possible to over-fertilize annuals, which can result in vigorous growth with lots of green foliage and greatly reduced flowering.
For more plant advice, contact the Plant Information Service at the Chicago Botanic Garden at plantinfo@chicagobotanic.org. Tim Johnson is senior director of horticulture at the Chicago Botanic Garden.
https://www.chicagotribune.com/2025/08/30/annuals-revive-tips-garden/
