Annuals
By Val Whitmyre, U. C. Master Gardener
Cosmos
An annual completes its life cycle—from seed to growth to bloom to seed—in one year or less, while a perennial may endure many years. If winters are warm enough where you live, some annuals may become perennials. In my Napa Valley backyard, the annual pincushion plant (Scabiosa) is a perennial.
Between the annuals and perennials are the biennials, such as hollyhocks (Alcea rosea) and foxgloves (Digitalis purpurea). These plants' growth cycle is two years, with the flowers blooming in the second year. Hollyhocks reseed in my garden, as do many other plants. However, with our mild winters, my hollyhocks survive from year to year, behaving more like perennials.
Start annuals from seeds or buy young plants. If you plant seeds in small pots, be sure the pots are clean. Before planting, submerge the containers in a solution of one part bleach and nine parts water and let them dry in the sun. This step will help prevent damping off, a disease that kills tiny seedlings. It's also a good idea to use a disease-free seed-starting mix from the nursery.
Within a few warm days, two tiny leaves will appear. When plants develop "true" leaves—the second set to appear—and seem to be strong enough to transplant, transfer them to the garden bed. I use a weak solution of fish emulsion every time I water, to baby them along for the first few weeks.
Some seeds have hard seed coats. To promote faster germination, scarify the seeds by making superficial scratches on them with sand paper. Soaking hard-coated seeds, such as sweet pea seeds, in water for a few hours will also hasten sprouting.
Some annuals reseed so readily that they may be considered weeds, as is the case with California poppies and forget-me-nots. Forget-me-not seeds stick to clothing, shoes and gloves, so you might find these plants everywhere in your garden and your neighbor's.
Most plants are subject to some diseases and pests, and annuals are no exception. Snails and slugs find most young annuals attractive. They hide during the day but feast at night, chewing on tender leaves and flowers. Use pet-safe bait or hand pick. Snails are so prolific that it is practically impossible to rid a garden of them.
In April and May, the budworm appears. It eats its way through flower buds from the inside out, then moves to the leaves. The worm is hard to spot as it takes on the color of the leaves. Budworms are common on petunias and geraniums. Remove all chewed blossoms.
My nemesis is the cutworm. Just when you think you have healthy blooming annuals, they wilt and fall over. Cutworms hang out in the top two inches of soil, munching on tender new roots. Rake away the two top inches of soil before you plant, or purchase a snail bait that includes something for cutworms.
Annuals come in all colors, so you can plant your favorite combinations. Pastels have a calming effect and seem to recede, while warm colors like yellows, oranges and red advance and dominate cool colors. Always include white to give deep colors more contrast. To create a more dramatic statement, plant in groups rather than rows. Groups create a focal point, while your eyes have a tendency to wander along rows looking for a focal point.
If you buy young plants, your best buys are four-inch containers rather than six-packs. Four-inch plants will provide more color sooner and won't be as susceptible to chewing pests. Also, fewer plants will fill the garden plot. Most annuals like a sunny spot, but impatiens do well in dappled sunlight.
A few of the most common annuals are petunias, violas, sunflowers, zinnias, ageratum, alyssum, snapdragons, cosmos, impatiens and lobelia. My favorites are violas, which include new hybrid pastel pansies, pure yellow violas and Johnny-jump-ups. 'Penny White' viola reseeds freely, so you'll only have to buy it once. You may also find Johnny-jump-ups reseeding throughout your garden, but they are more welcome than invasive.
I plant all my annuals in pots now because I can give them closer attention and move them into the shade during summer heat waves.