Easy Maintenance for Annual Flowers

By Laurel Aiello | Fort Collins Nursery

Simple Summer Care Keeps Annuals Blooming Strong

By mid-summer, some annual plants start to look a little haggard. Whether they’ve gone too dry on occasion or they’re lacking the nutrients needed to continue blooming, there are many things you can do to help them perk back up. These tried-and-true tips are a great place to start.

Prune back foliage

If parts of your plants are leggy or crispy, prune them back to encourage new growth. Think of calibrachoa, for instance: Over time, their stems can grow lanky, with sparser foliage and fewer flowers on long, stringy stems. Pruning the stems just above a node—where the plant sends out new leaves—signals to that node that it’s time to bush out. The same rule applies to petunias, bacopa, and other vining plants. Keeping these annuals pruned will result in neat, compact foliage and plenty of fresh blooms.

Deadhead old flowers

Another way to revive tired annuals is to remove their spent blooms. This keeps the plants from going to seed and forces them to focus on producing new flowers. Not all annuals have to be deadheaded: Some cultivars are “self-cleaning,” meaning they shed old flowers on their own (think Supertunias, Million Bells calibrachoa, and SunPatiens). But many classic annuals, like petunias, zinnias, snapdragons, dahlias, geraniums, and marigolds, need a little help. It takes some time, but with music or a podcast to keep you entertained, it can also be meditative.

Fertilize regularly

Annual plants exert a lot of energy to produce flowers continuously, so they need food to refuel themselves. Since they quickly deplete the nutrients in potting soil, it’s recommended to apply fertilizer once or twice per week if you want abundant blooms throughout the summer. An all-purpose plant food should do the trick, though there are bloom-specific fertilizers with higher amounts of phosphorus, the nutrient responsible for flower production. Pro tip: Apply a flowering fertilizer after pruning and deadheading your annuals to give them an extra boost of energy.

Water deep and often

Annuals are thirsty, too, though some are semi-drought tolerant, including gazanias, gomphrena, lantana, and portulaca. Potted annuals dry out much quicker than those in the ground (especially full sun annuals) because they have limited root space, often becoming root-bound by mid to late summer. Make sure to water those annuals deeply and frequently, preferably in the morning, by aiming the hose or watering can at the base of the plant. Not only does that help prevent evaporation, but it also reduces the risk of fungal spores spreading.

Check for pests

There’s nothing worse than seeing aphids, spider mites, whiteflies, or other pests eat away at the annuals you’ve been tending to for months. Check your plants regularly, including the underside of the leaves, where insects like to hide and often leave webbing or a sticky residue. Treat any affected plants with neem oil or Safer Soap, and spray them again in a week if needed. If the problem persists, alternate the treatments until the pests are gone. Pro tip: Spray the plants when they are shaded so that the sheen of the oil doesn’t magnify the sun and burn the leaves.