Few of us think much about annuals until it’s that time of year when you’re in the midst of a planting mania. However, as gardeners, it behooves us to occasionally ponder the difference between an annual plant and one that is a tender perennial – sometimes referred to as being “half-hardy.” A tender perennial is one that typically will not survive our cold January nights.
Annuals vs. Perennials
The two types of plants are with us for entirely different reasons. An annual desperately wants to go to seed. If you think about basil and coleus, they spend the second half of the summer trying to release their seeds while you spend that part of summer endeavoring them from doing so.
Although there are short-lived plants such as daphnes, perennials typically are here for the long haul. Generally, they spend their first year getting established in their new home. Some, like baptisia, will simply sit there, doing little above the ground, while it’s spending its energy putting down its taproot. Others, such as phlox, will grow somewhat during that first growing season, thereby giving us a glimpse of its future potential.
However, no perennial will reach its full promise during its first growing season. This is an important rule to keep in mind when you’re reaching for that tender perennial in the nursery.
For three years I tried to grow Michael Dirr’s introduction, Lantana ‘Chapel Hill’. It produces lovely, pale-yellow flowers, flowers that I lusted to have in my garden. Surely a lantana with the designation ‘Chapel Hill’ would survive in Chapel Hill. I knew enough about lantana that I should refrain from cutting back the branches until new growth reappeared in the following spring.
The only trouble was that no new growth ever reappeared. Clearly Lantana ‘Chapel Hill’ wouldn’t work for me as a perennial – but it also flunked its role as a would-be annual. Each year I would dutifully plant it and each year it just sat staring at me while it was establishing a root system that wouldn’t survive the coming winter. In other words, this half hardy perennial was behaving as a perennial.
Now, not all perennials are slow growing. Some, like the ornamental grasses, grow rather quickly so a tender grass might soothe your need for instant gratification but generally speaking, most tender perennials are going to cause initial disappointment.
I used to regard annuals as rather garish plants that had little personality. I belonged to the “if you’ve seen one petunia, you’ve seen them all” camp but I have come around to new thinking of these workhorses in the garden. Every gardener has a need to plug up holes. If you plant perennials the proper distance from one another, you’ll have a hole until the perennials have time to meet each other halfway. A lovely temporary answer is to plant an annual to fill the gap.
Some annuals can make a breathtaking statement. Years ago, a friend gave me seeds from opium poppies that grew in her garden. Now Papaver somniferum is an incredibly gorgeous species that comes in a range of colors. They are among the first flowers to appear in spring while it is still cool. En masse, they are spectacular. Because they bloom on the early side, they do not disrupt or compete with the perennials in that part of the garden. By the time they have gone to seed four weeks later, it’s time to pull them up, saying, “Sayonara.”
There are several tricks to growing opium poppies: (1) These are sun lovers so plant them in the sun; (2) Let them go to seed – this is vital if you want them to return; and (3) Do not cover the seed area with mulch – these seeds dislike mulch. If you tend to them properly, you will have a lovely annual that comes back year after year.
Now some annuals that reseed are not nearly as welcome as the opium poppy. Cleome is such a plant. Not only does it have prickers along its stem, it has a weird aroma, and is a profuse seeder. The seedlings will compete with perennials as they appear during the height of the growing season.
Basically, planting a successful garden comes down to this: Be knowledgeable about what you plant. And if any readers have successfully grown L. ‘Chapel Hill’ as a perennial, I’d love to hear from you.
After joining the Durham County Extension Master Gardeners in 2003, Kit Flynn now has emeritus status. She writes gardening articles for the Durham County Extension Master Gardener newsletter, an online magazine “Senior Correspondent,” and “The Absentee Gardeners” column for “The Blowing Rocket” with Lise Jenkins.