Make Your Annual Flowers Perennials

November 14, 2013 | By | Comments (7)
Geranium

Like this geranium, many flowers sold as annuals in cold winter climates can become perennials by overwintering them inside. Photo by Steve Bender.

There’s a freeze warning out tonight in Grumpy’s neighborhood, which means his annual flowers are doomed. Or are they? Four years ago, Grumpy’s wife bought a one-gallon, coral-pink geranium and planted it in a concrete planter by our front steps. It’s still blooming. How can that be?

It’s because there are two kinds of “annuals.” The first are true annuals, like cosmos, larkspur, bachelor’s-button, celosia, and common sunflower. After they flower, they set seed and die. This is genetic programming you can’t change. The second are tender perennials we treat like annuals because of our cold winters. Remove the cold, give them winter sun, and they become perennials that you can enjoy for years. This is what we did with our geranium.

Come Inside, My Pretty

Geranium

The dang planter weighs a ton, so moving it takes a hand-truck. Photo by Steve Bender.

Fortunately, our garage has windows to let in sun and it stays about 55-60 degrees in the winter. So the geranium does fine. Oh, it’ll shed some leaves because of the dimmer light, but I just pluck them off. Common geranium (Pelargonium x hortorum) has succulent stems that become woody over time. I’ve seen older specimens pruned into small trees. It needs very little water in winter — just enough to keep it from wilting — and zero fertilizer.

Achtung! Very important! (Turn off Hoda and Kathy Lee — trust me, you won’t miss a thing.) Before bringing any plant indoors that’s spent the summer outside, closely inspect it for any pests, like aphids, spider mites, scales, mealybugs, or white flies. In close quarters, one infested plant could quickly infest them all. So spray the foliage thoroughly — both upper and lower leaf surfaces — with paraffinic horticultural oil or insecticidal soap (both are natural and very safe) to kill hitchhiking pests, their larvae, and eggs. When it dries, bring the plant indoors.

Other Annuals You Can Make Perennial

Begonia

Common waxleaf begonias are easy to overwinter indoors in a sunny window. Photo: kafka4

1. Angelonia
2. Begonia
3. Coleus
4. Common heliotrope
5. Copper leaf
6. Dusty Miller
7. Impatiens
8. Lantana
9. Madagascar periwinkle
10. Pentas
11. Persian shield
12. Polka-dot plant

COMMENTS

  1. VB

    Okay, I’m trying it this year with my huge begonias and geraniums. I swear I have perennial lantanas. Are you familiar with them? Or I am mistaken about the name?

    November 14, 2013 at 12:11 pm
  2. Dea

    Here on the Houston Gulf Coast, Dusty Miller and Begonias are true perennials. They’ll overwinter just fine in the flower bed unless we have an exceptionally cold freeze (below 30 degrees for more than 8 hours). And even then, since that’s usually a once-a-winter event, you can still overwinter them in beds if you cover them properly. My new beds have Dusty Miller just planted, but my neighbor has some that are more than five years old and never moved from the flower bed on the east side of the house. In Huntsville, which is about 45 miles north of us, my mother over-wintered begonias in her flower beds, only having to cover them once or twice each winter. One of them was over 10 years old, and HUGE! It was about four feet in diameter. (In the interest of full disclosure, my late mother had a green thumb that went clear up to her elbow — she could grow ANYTHING in the garden!)

    November 14, 2013 at 12:46 pm
  3. Big C

    They’re all perennials — just tender ones, which means in some areas they will die and in some they are fully hardy. It depends on where you live. Lantanas are hardy to zone 8, but they can stay in the ground even in colder climates. They might die back, but they’ll come up again in spring.

    November 14, 2013 at 12:53 pm
  4. VB

    Yes they die back, and come back larger each year. I have to prune them back to keep them from covering walkways! I’ve been dividing them and transplanting to keep them from being larger than I want.

    November 14, 2013 at 1:11 pm
  5. sharon holmes

    I have a beautiful two-year-old red greranium, and will attempt to overwinter my hibiscus this year!

    November 14, 2013 at 2:19 pm
  6. Colin McKnight

    I had a pair of red geraniums that I overwintered in a south facing window in upstate NY for about 8 years. They had gotten leggy, so I trained them into lollipop topiaries that summered on either side of the front walk. The stems do get pretty woody, as Grumpy said.

    November 14, 2013 at 5:02 pm
  7. Cindy S

    I had 6 geraniums that I kept for over 8 years by moving them to the garage for the winter. I cut back on the water and trimmed back the plant to about 2-3 inches high. After the last frost in spring I would set them out to get rain and sun, give them a shot of fertilizer, then after a couple of weeks, I would move them back to their summer spots and resume routine water and feeding schedules. They would come back nice and full. However, this year I jinxed myself. After bragging about how well they overwintered, they decided to make me a liar and croaked. Now I’m having to start all over again with fresh plants. This winter I’m altering the “minimal water” rule to at least a pint of water a week per 12″ pot. We’ll see how they do.

    November 16, 2013 at 10:55 am