Annual Flowers Growing flowering annuals from seed is an easier, cheaper solution to purchasing live plants. by By Pat Roome, CPH
Pat Roome Landscape Design Everyone loves summer flowering annuals but purchasing and replanting them every year can be expensive and time consuming. Many of the most attractive annual flowers will never be found in a nursery pack, primarily because the roots and stems are too fragile for the necessary handling and transplanting. Salpiglossis for example. Direct seeding of these plants gets over these problems.

Salpiglossis Painter Tongue, 15" tall, with wide range of colors

Annuals are characterized as hardy annuals: HA; and half-hardy annuals: HHA. Tender perennials that bloom their first year such as Heliotrope are treated as HHA in the Northwest. Hardy annuals will germinate in cooler soils and will survive a light frost while the tenderer HHA should be seeded after the middle of May - a fairly safe date for Western Washington. HA can ordinarily be seeded in April and many of them will re-seed for several years. Among my favorites are Phlox drummondii HHA. It blooms in tidy mounds in many colors until frost. It requires no deadheading and is drought tolerant. Deadheading is the removal of the spent flowers - it makes most annuals bloom longer.

Escholtzia 'Thai Silk' California Poppy, 12-15" tall / 1-2' wide, will re-seed, colors cream, orange and pink

Most annuals prefer full sun although Ageratum, Heliotrope and Pansies will tolerate some shade. They also prefer well drained soil. If your soil is too heavy or wet, build up a raised bed. Mix three inches of 50/50 soil/compost mix into the top three inches of your soil, then spread three more inches of the 50/50 mix on top. You can improve a well draining sandy soil by mixing in two inches of compost. Add Chicken manure or a 3- month timed release fertilizer in pellet form. Rake the soil area smooth before seeding. The larger seeds that can be handled easily are planted individually at the desired spacing. For very fine seed, mix it with a little dry sand and sow it as thinly as possible. Cover the seed with compost per packet instructions. Water by hand gently and keep the soil surface moist until germination - a week or more.

In June or when the seedlings have developed their first set of leaves, thin out extra plants; scissors work better than pulling and avoids disturbing the plants that will remain. Remove weed seedlings in the same way. As your flowers begin to develop spread up to an inch of compost between the plants; this prevents germination of weeds and keeps the soil cool and moist. With this sort of soil preparation, I have found watering necessary only three times during the summer. Set a soaker hose for three hours or a sprinkler for an hour or two. Check with a trowel to see moist soil in the root zone. Plants such as Calendula or Escholtzia(California Poppy) do not require to be watered at all.

Plox drummondii, 12"tall / 2' wide, mounds

Attractive annuals that are usually found potted in nurseries include: Marigold, Pansies, Ageratum, and Lobelia. California Poppy, Calendula, Lavatera, Lobularia, Nasturtium, Nigella, Phlox, and Salpiglossis are usually garden grown from seed.