Perennials
by Cecile Garrison, UC Master Gardener

I love perennials! They attract butterflies and hummingbirds and provide glorious flower color almost all year. What do I mean when I say perennial? I'm talking about flowering plants with herbaceous or fleshy stems, which usually die back to the soil's surface before winter. Some have woody stems that don't die to the ground but do require judicious pruning in spring just before new growth emerges. Horticulturists define a perennial as any plant that lives for three or more years. Well, that would include thousands of species, from dandelions in lawns to giant redwoods in Sequoia Park.

The root system of perennials is what sets them apart from annuals and biennials. Annuals sprout from seed, bloom, bear seed and die in one season. Those are the pansies, snapdragons, marigolds and zinnia that we spend a fortune on each year. Biennials also sprout from seed, spend their first year growing, their second year flowering and producing seed, and then die. Foxglove, Canterbury bell and Sweet William are just a few examples. Since annuals and biennials die, I prefer perennials because they last for years with minimal care. I still have peonies that were brought to California in the thirties by my husband's family. Some people can trace their heirloom plants over a hundred years!

LEARN BY MISTAKES
I attempt to have something blooming in my garden at all times and perennials are my mainstays. One challenge is to have lots of blooms without completely taking over the garden. Some of my mistakes have been rosemary, gaura and Mexican primrose. They were so pretty at the nursery in their small pots that I bought several of each. My garden was completely overtaken in two seasons and I gave away all but one of each. I learned once you buy a six-pack of Mexican primrose you and your neighbors will have them forever! They have an invasive underground root system that spreads as far as you let them. I thin them by pulling out hundreds at a time by the roots. I can't bring myself to eradicate them completely because they bloom beautifully from April until first frost.

KEYS TO SUCCESS
Perennial gardens require fast draining, moisture retentive, nutritious soil. Soil must be loose enough to allow water and air to reach roots. New gardeners often keep beds too wet and don't realize that plant roots need air to grow. Also, bacteria in the soil assist the nutritional plant process and they cannot live without air. Try not to walk on flowerbeds as this causes soil compaction. One important soil additive is composted steer manure. I put two to three inches a year on every flowerbed. It is packed with soil organisms!

My roses get an application of a long acting systemic fertilizer. It keeps aphids at bay for several weeks and helps prevent powdery mildew and fungal infections. Occasionally I use a water-based fertilizer to give other flowers an extra little boost.

Perennial gardens need room for air circulation around foliage to prevent diseases such as powdery mildew. Leave 2-3 feet between plants and the house or fence. Most perennials need six hours of sun to maximize bloom. Be sure to choose plants adapted to our Valley. Select from the following list.

FULL OR PART SUN: Agapanthus, alstroemeria (Peruvian lily), astilbe, butterfly bush, candytuft, canna, chrysanthemum, clematis, columbine, coneflower, coral bells, coreopsis, daylily, dianthus, foxglove, gaura, geranium, herbs, hollyhock, honeysuckle, lantana, lavender, liatrus, lobelia, lungwort, Mexican heather, Mexican petunia, passion vine, penstemon, phlox, rosemary, salvia, scabiosa, statice, verbena, veronica, and yarrow.

SHADE: Ajuga, baby tears, begonia, bleeding heart, caladium, ferns, geranium (Johnson's blue) heliotrope, hostas, impatiens, ivy, and star jasmine.

Perennials are great in containers, rock gardens, and bordering lawns, walkways, and driveways. Try mixing perennials in your garden this spring. They provide a succession of vivid colors plus they are hardy, adaptable and require little maintenance. Perennials allow you more time to enjoy your garden.

April 25, 2002