Getting the most from annuals

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There’s nothing more temporary than annual flowers and, paradoxically, nothing better for long-lasting color in the summer garden.

Shrubs and perennials rarely are good for more than two or three weeks of blossoms, but annuals keep flowering from late spring until shorter fall days cause them to decline or frost cuts them down. While annuals have to be planted anew each season, that’s not necessarily a bad thing if you enjoy the chance to give the garden a fresh, new look from year to year.

Right now the garden centers are full of inexpensive six-packs of annuals just begging to be taken away and given a good home. Spend a little more, and you can walk away with a planted container or hanging basket already in full bloom. It’s hard to resist the temptation to spread a little instant color around at home when the spring planting itch is at its itchiest.

But if you cast your mind back to last summer, you may recall that your little annuals, initially in their prime, gradually went downhill or failed to thrive. As with any aspect of the gardening game, there are tricks to getting the most from your garden center haul.

Plants already in flower are what sell best, so garden centers plan to have their flats and containers in bloom when customers are ready to dig in and get planting. It’s convenient from a planning point of view to see exactly what shade the flowers will be, especially when choosing color-coordinated companions.

But botanically speaking, a tiny plant in bloom has been pushed unnaturally hard toward maturity and its root system may already be pot-bound and squeezing out of its pot in search of nutrients. The best buy is a plant in bud, not in flower, but a little care at the outset will help get your seedlings off to a good start no matter what they look like.

For starters, don’t leave your plants to fry out in the hot sun or abandon them in the car. Cart them off to a shady, sheltered place and give them a good soaking. They need to go into the ground or containers as soon as possible but as we all know, procrastination happens.

When you’re ready to plant, pop each seedling out of its container and spend some time gently roughing up the root ball. If it is a badly congested tangle of tightly packed roots, I take a sharp scissor and make a few vertical slices right through the root mass. This encourages new feeder roots to form which will support good leaf growth and flower production.

I know it goes against every inclination, but once you have your plant positioned, steel yourself and cut off the flowers and buds. Initially, you want seedlings to spend their energy producing roots and shoots that will sustain them through the long season ahead. Pinch back any leggy stems as well to promote compact growth and vigorous branching.

With a shot of fertilizer and conscientious watering, the plants will soon gain some size and produce a new flush of buds. Regular feeding and adequate irrigation are really the keys to keeping annuals producing as they should. You’ve already removed them from their life-support system at the garden center or greenhouse, where they have likely enjoyed fertilizer-laced drip irrigation all their young lives. 

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Some plants like impatiens drop their dead flowers cleanly, but most annuals need regular grooming. Removing spent flowers (a chore known as deadheading) prevents the plant from setting seed, a signal that its mission in life has been accomplished. Once the next generation is assured, annuals often go downhill. Many gradually come to have just a few flowers at the tips of long, straggly stems – petunias are notorious for this unattractive look.

The cure here is to again take up the pruning shears and cut the plants back sharply. This should stimulate a new cycle of vegetative growth (leaves and stems) followed by a fresh round of flowers. The idea is to keep annuals perpetually striving to produce flowers while thwarting their inclination to set seed.

If your annuals are in pots, you can stagger the major surgery and move recovering plants off-stage to a less conspicuous position while enjoying the containers that are at their peak. When I’m feeling especially ambitious, I will switch out the hanging baskets that hang from my porch eaves, replacing them with better-looking plants while the originals are regaining strength.

Don’t forget the power (and ease) of foliage plants, which are colorful enough without flowers. Coleus, sweet potato vine, caladiums and Persian shield will make an effective splash without the extra step of weekly deadheading.