There probably aren't any flowering plants that perform nonstop. If you are looking for types that bloom most of the year in California, however, your best bets are tender perennials. Many of them are day-neutral plants, meaning they don't require a certain number of daylight hours to set buds. Some houseplants, perennials and annuals can also carry on for months, though a few of the fast-growing annuals accomplish that feat by self-sowing.
Many of these plants are considered container annuals in colder climates but can attain the height of shrubs in California. Most have one season of the year when they perform best, but they continue to throw out occasional flushes of flowers as long as the weather allows them to do so. This group includes: Abutilon (commonly called flowering maple), Allamanda (golden trumpet), Anisodeontea (cape mallow), Euphorbia milii (crown of thorns), Euryops pectinatus (yellow bush daisy), Heliotropium (cherry pie), Lantana, Pelargonium (annual geranium), Scaevola (fan flower), Tagetes lemmonii (Copper Canyon daisy) and many others.
Gesneriads are generally the most dependable bloomers among houseplants, except for bulbous varieties such as Sinningia (gloxinia) that require dormant periods. Types such as Aeschynanthus (lipstick plant), Chirita, Codonanthe, Nematanthus (goldfish plant), Saintpaulia (African violet) and Streptocarpus (cape primrose), can continue to flower off and on all year. As these plants don't like direct sunlight -- and some have fuzzy foliage that can't tolerate much rain -- they are usually grown indoors or on shady porches.
Perennials and Biennials
Most hardy perennials and biennials only bloom for about a month to six weeks. Plants such as Bidens (beggarticks), Coreopsis (tickseed), Erysimum (wallflower), Gaillardia (blanket flower), Geranium (cranesbill), Meconopsis (Himalayan poppy), Oenothera (evening primrose), Salvia (sage) and Scabiosa (pincushion flower), however, can flower for months, providing that they like their location. With perennials, duration of bloomtime varies widely, depending on which species or cultivars you grow. Some of the most enduring types include Bidens ferulifolia "Goldmarie," Coreopsis verticillata "Moonbeam," Erysimum "Bowles Mauve," Gaillardia grandiflora "Goblin," Geranium "Rozanne," Meconopsis cambrica, Oenothera macrocarpa, Salvia chamaedryoides and Scabiosa columbaria "Butterfly Blue." Since roses are day-length neutral, ever-blooming varieties of them can continue to flower almost year-round as well in areas where they don't freeze.
Calendula (pot marigold) was named for its ability to bloom in almost every month on the calendar. Its flowers diminish in size during the summer, as it doesn't like hot temperatures, but it generally returns strongly in the fall. Other annuals known for their long flowering include Lobelia, Nemesia and Tropaeolum (nasturtium). If you wish to prolong their performance, be sure to snip off faded flowers to prevent them from going to seed. Otherwise, the plants assume they have accomplished their purpose -- and stop blooming.
Your Planting Articles
- The New Sunset Western Garden Book; Kathleen Norris Brenzel
- Perennials for Northern California; Bob Tanem and Don Williamson
- The Telegraph: Top 10 Tender Perennials for an Indian Summer; Sarah Raven
- Pat Welsh's Southern California Gardening: A Month-by-Month Guide
- Organic Gardening, Apr 2006: Long-Lasting Perennials; Sally Roth
- Jupiterimages/Photos.com/Getty Images