As I explained in my Introduction to Annuals, they can be summarized as follows: seed, germinate, grow, flower, flower, flower, I am so pretty, flower, flower, oh my biological clock is ticking, make seed, die. Time elapsed, one year or less.
Perennials are plants that grow for more than a year (assuming they live; it’s a life style, not a contract with God). They take their time; frequently they don’t even bloom in the first year of growth after the seed germinates.
When they do get around to blooming, perennials have shorter blooming seasons than annuals, or, if they bloom for several months, usually the first few weeks are intense and the re-bloom is more sporadic, sometimes requiring some encouragement on the part of the gardener. This might be something like shearing a couple of inches off of the top of the plant to remove the old dead flowers
Perennials tend to be either cool weather, late winter/spring bloomers or warm weather summer bloomers (but not both). There are even a few fall bloomers. The summer bloomers tend to have longer blooming periods than the spring bloomers.
We know a few things about garden center shoppers. We know that most of you a) shop in the spring, and b) you tend to buy what is in flower when you shop. Because a lot of the fun of perennial gardening is watching things change from day to day and week to week as plants grow and come into flower, you really should visit the garden center a couple of times in the summer to see what’s currently in bloom. Really. It’s for your own good.
Of perennials, it is said that the first year they sleep, the second year they creep, and the third year they leap. So, during the first year after you plant your perennial, not that much happens. The second year (after the first winter) you have more blooms on larger plants, and the third year, they really hit their stride with much larger plants and heavier bloom. Assuming everything goes right.
Most perennials die completely down to the ground in the winter, overwintering with living bits below ground. Or, they overwinter with small tufts of foliage (leaves) above the soil. Technically, these are “herbaceous perennials.” While we are jargoning, we may as well toss in hardy, which means they tolerate some below freezing temperatures. So what we are talking about are hardy herbaceous perennials: you’ll do fine if you just say “perennials.”
There is another outdoor herbaceous group that falls between the annuals and perennials, the biennials: plants that grow without flowering the first year, flower the second, and then die (so bi-ennial; two years). These include cabbage, parsley, and foxgloves. These are sold with the vegetables, herbs, or perennials, wherever they seem to fit the best. There aren’t that many.
Why use perennials?
Most people do it to save the effort of replanting annuals each year. This does save some planting time, but for a perennial garden to look good, it does require some care—cutting back old flowers and so on—so planting perennials doesn’t save much time, it just spreads it out. The real reason to choose perennials is that it allows you, should you be inclined, to “paint” with flowers. Perennials change in many dimensions over the season—height, width, color; texture of foliage (fine or broad leaves); how one color plays off the colors of surrounding plants. So, you really get to play. If you enjoy repainting your walls with new colors, then you will enjoy painting the garden with perennials.
Perennials are best planted in groups, three or five plants of a given type. If you have a big enough space, you can repeat the group in several spots to “unite” the garden.
by Larry Hurley
Photo by Susan Harris of the healing garden at an AIDS services center in Buffalo.