Q: My annuals (petunias, verbena, and vinca) have gotten very leggy already, and their leaves are rather pale. What can I do to revive them so they keep blooming for the rest of the summer?
A: Because annual plants expend a good amount of energy producing flowers prolifically (that’s usually why we plant them), they can start to look less than stellar as we get further into the growing season.
Since your plants are already leggy, cutting them back by about 1/3 to ½ above a leaf or pair of leaves should help promote healthy new growth.
Since annuals grow so quickly, it’s important to keep up with their water and nutrient needs throughout the growing season. Applying a slow-release fertilizer according to product instructions early in the season can take care of nutrient needs for the whole summer. You can also opt to feed with a water-soluble fertilizer every four to six weeks. Regular deadheading or pinching will add to your enjoyment of these plants by increasing the number of blooms and keeping them tidy.
Write to the Missouri Botanical Garden’s Center for Home Gardening at plantinformation@mobot.org or the Horticulture Answer Service, 4344 Shaw Blvd., St. Louis, MO 63110.