Perennial or Annual?

Gardeners often face the choice of filling a container or a space in their xeric landscape with either an annual or perennial. And new gardeners might have a hard time knowing whether a plant they spot and love will come back in their garden next year. Let’s take a look at annuals vs. perennials, especially in xeric landscaping.

cosmos and agave in New Mexico garden

These agave are xeric, but apparently so are these cosmos, annuals that just pop up from old seeds each year, to the point we had to thin them to give the agave room.

First-time gardeners might not get the difference between the plant types. It’s easy to remember if you think about the terms attached to each plant: A perennial lasts three years or more, but an annual is there only for this year, just like the root of the word (annus, Latin for year).

So, how do you know when you want a perennial and when you want an annual? Here are a few scenarios:

For containers, it’s often best to go with annuals. Unless you have plenty of sunny indoor space and a strong back, you’re better off placing annual flowers into most of your containers, just for the season. Of course, succulents can easily live indoors in sunny locations, as can some herbs, bedding plants and houseplants. I love planting just a few containers each year in front of my house, and at our last home, we had one annual bed that we changed out each year, also adding pansies for winter color. It’s a small splurge.

But if you’ve got a huge raised bed to fill, go with bulbs and perennials, or maybe spring-blooming bulbs, overplanted with annual seeds that come up later in summer, after your bulbs are done blooming. Seeds cost less if you’re willing to wait for the plant to grow, then bloom. Having said that, one of the benefits of buying annual plants is instant gratification!

xeric annuals and perennials

I think I just showed the combination of yarrow and gaillardia, but I can’t get over how great the perennial and annual look together.

Here are some of my favorite low-water annuals, many of which are wildflowers that will reseed:

  • California poppy
  • Cosmos
  • Desert marigold
  • Portulaca (Moss rose)

For most xeric gardens, however, you can’t beat a hardy, low-water perennial that blooms year after year. All you usually have to do is cut back dead branches or flower stems and wait. A few cautions with perennials: Some spread, even though they’re xeric plants. And sometimes, you have to cut them back drastically to keep your garden under control and prevent one perennial from competing too much with others, such as shading another plant that needs six hours of sun a day.

gray santolina and cherry sage

This gray santolina. along with a few neighboring perennials, is blocking sun to the red sage next to it. I love both plants, so we might move the sage to a sunnier location.

Here are a few of my favorite low-water perennials:

  • Coreopsis
  • Echinacea, or coneflower
  • Gaura
  • Lavender
  • Penstemon
  • Sedum
  • Santolina
  • Sage – any perennial salvia and sage
  • Yarrow

How do you tell an annual from a perennial when making a purchase? If your nursery doesn’t have the plants sorted by annuals vs. perennials, you can always ask. Another clue is that many annuals are sold in six-packs or similar packaging for several smaller plants. Perennials tend to come in pint size, gallon pots and up. But that’s not always the case. And a particular flower might be available as both, so check the tag or ask nursery staff. An example is the salvia, which comes as several great perennials. But there is a red salvia that only works as an annual, at least in my zone.

larkspur annual

Pink and purple larkspur, the annual version of Delphinium. These reseed under our red bud each year with no effort on our part.

That takes me to my final point: One gardener’s perennial might be another gardener’s annual. In other words, zone and general conditions can alter a plant’s ability to endure for more than one season. Geraniums are container plants or annuals in the mountains and high desert of New Mexico, but might be perennial in southern California. And just to add to the confusion, hardy geraniums (of the genus Geranium), are different from Pelargoniums, common geraniums, such as the scented flowers. And gaillardia, or blanket flower, is one of my favorite plants that might be an annual or perennial, depending on the cultivar and conditions. Ours simply reseed throughout the garden year after year.

I added several other photos of annuals and perennials mentioned in this post to the Photos page.

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