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.

Harden Off Houseplants for Their Summer Vacation

When warm days—and especially warmer evenings—finally arrive, our houseplants are more than ready to move outside. It’s easy to tell. They look a little leggy and droopy. And although I said they are ready for a summer vacation, in reality, they’re taking an eight or nine month winter vacation inside. Because plants grow naturally outdoors, of course!

Geranium hardening off outside.
Geraniums are annuals in our climate, but I love how they bloom indoors in sunny windows all winter.

I really only have geraniums (Pelargonium spp.) right now, along with one canna that I keep in a huge container. It’s my ode to the tropics, and although it hasn’t bloomed again, I love it purely for the leaves. This year, I plan to cut it back and divide it, giving a few bulbs to family members who live in a warmer climate. Maybe dividing and cutting it back will force energy into blooming. We’ll see!

tropicanna canna
This Tropicanna canna is from Tessalaar Plants, and would have trouble making it here, plus uses too much water. But I have kept it alive in a container purely for the leaves. The flower is bright orange and gorgeous!

One reason I have few house plants is time, another is water savings, and most of all, it is lack of space and containers. My succulent-collecting husband has taken up most of the sunny space with propagation, and used lots of the containers. But I enjoy his cactus habit!

The main point to remember when bringing all of your houseplants out for the first time after their “winter vacation” is to introduce them slowly to the outdoor climate again. For most houseplants, that means bringing them into a shady, protected area first or leaving them out on a relatively calm but cloudy day. And bring them back in the first few nights if there is any chance that temperatures will approach frost.

aloe vera plants
Aloe vera plants harden off on a partly sunny day in preparation for the summer outside.

The cacti may be able to sit in full sun from the start; in fact, they probably need it. But if it gets blazing hot, bring them in before day’s end, and don’t subject them to cool desert evenings until they’ve at least been outside through dinner hour. If you don’t want to make the indoor/outdoor trek every night, you can cover your most sensitive plants with landscape fabric until they harden off and the nights warm up. The fabric also can help shade them during the hottest part of the day if temperatures shift while your plants are acclimating.

Make sure your plants are healthy and ready for the move outdoors. I cut my geraniums back quite a bit and usually add a little bit of soil or compost to the pot. If they’re in really bad shape, I will repot them. But they tend to bloom better if slightly root bound. Then I give them a good drink and put them in dappled or partial shade the first few days, gradually giving them a little more sun.

geraniums cut back for hardening off
I cut these geraniums back severely and added some compost, because they did not fare as well as my others. They need repotting next year. Note the requisite gardening gloves and phone…

High-desert Succulents

They’re the ultimate in low-water gardening. Succulents store water and grow slowly, making them adaptable to the dry climate of the desert Southwest.

Cacti are succulents that usually are small and round and have spines, branches or leaves. Succulents also can have the same characteristics, but the spines don’t arise from a spine cushion, or areole. You’ll only find cacti in the Western hemisphere. The picture that so often comes to mind is the saguaro surrounded by blowing dust in the dry, hot desert.

And that’s often where you find cacti, especially here in New Mexico and neighboring Arizona. My husband loves succulents and we enjoyed a trip a few years ago to the Desert Botanical Garden in Phoenix, where we saw so many varieties, most of which couldn’t take the cooler temperatures we have at our higher altitude.

barrel cacti in Phoenix
There’s at least one yellow bloom left on one of these great barrel cacti at the Desert Botanical Garden in Phoenix.

But who says you can’t have succulents at 6,000 feet of elevation? Several natural varieties of succulents thrive in the high desert. Hens and chicks, ice plants, several varieties of agave, and several native plants come to mind, such as prickly pear and devil’s head (also known as horse cripplers).

devils head or horse crippler cactus
The devil’s head blooms in spring with light pink, papery flowers full of seeds. It’s native to southeastern New Mexico.

And you can have all kinds of fun inside your house, assuming you’ve got a good south-facing window, sunroom or greenhouse to winter over potted succulents. I think I mentioned how much my husband loves them? I have a geranium on this wall; the rest of the plants are succulents. He’s even propagating some new ones. We need a greenhouse soon!

succulents on south wall
Yep, that’s a light layer of snow on the ground outside, but the succulents are toasty warm.

In case you think succulents are boring, think again. Aside from the many shapes and growth patterns, many of them flower. I’ll try to get some good photos of the devil’s head flowers, but for now, enjoy the delicate blooms on this crown of thorns (Euphorbia milii), which blooms all year long in a sunny location. It started out as a tiny plant from a big-box store and now is about two feet tall (after a nice trim to keep it bushy). There are a few propagating on that trombeil wall, too!

crown of thorns flower
The delicate flowers of the crown of thorns.
euphorbia milii
This crown of thorns started out just a few inches tall.