Gardening in Larimer County

Zowie!*!  Wow**?! Kazam*!*##.

Annuals show off all summer long and give you lots of  material for beautiful bouquets.  They germinate, grow, flower and set new seed in one year or less.  Nothing else rewards you with such a variety of colors, textures and shapes and blooms from spring to fall.

There are annuals from A (ageratum) to Z (zinnias).  Hardy annuals like larkspur and pansies can be planted in early spring or planted in late summer to overwinter and bloom early next spring.  These annuals will grow through the summer at higher elevations. Salvia, cosmos, gomphrena, and celosia are half –hardy annuals that are planted after the last frost date and will survive a light frost in the fall.  Plant or direct seed tender annuals like ageratum, cleome and zinnias when the ground is warm.

The cutting garden can be a separate garden or incorporated into the vegetable garden or perennial bed.  And, of course, annuals are the main ingredients in containers. Don’t worry about cutting the flowers and leaving holes in your landscape – the more you cut, the more they will bloom.

Annuals come in every color imaginable.  Pick flower colors that will enhance the décor in your home. Go with a single color scheme and vary the texture and shade with different plants or a harmonious color scheme that will unify your landscape. A complementary combination would be tall, blue ageratum with yellow marigolds.  A more “romantic” combination would be pink and white cosmos with pink malva and purple fountain grass. Sunflowers in the new shades of yellow to maroon make beautiful bouquets all by themselves.  Grow some of the new pollenless varieties like Sunbright or Sunrich Lemon.  And, for “knock your socks off orange” try growing tithonia (Mexican sunflower).

Keep annuals watered and use a mulch to reduce the loss of moisture.  Pull the weeds and feed with a 10-10-10 slow release fertilizer or use a diluted liquid fertilizer while planting and again just before blooming. Sow annuals like larkspur, cosmos, bachelor buttons and annual baby’s breath directly into the garden. Try ammi majus(Bishop’s Weed), Euphorbia Marginata, Malva Sylvestris a small hollyhock , and Gypsophila (annual baby’s breath) as fillers to add texture to your bouquets.

A starter cutting garden might include Rocket or Liberty snapdragons, Blue Horizon ageratum, State Fair and Blue Point zinnias, Versilles and Seashell cosmos, celosia Crista Chief and gomphrena Bi-color Rose. And, don’t forget the sunflowers!  Cut flowers in the morning after the dew has dried or early evening when the air has cooled.  Strip away any foliage that will be under water and place the stems immediately in a clean bucket of water.  A floral preservative can extend the vase life of your flowers by several days.  The preservatives are made up of sugar, an acidifier like citric acid and a biocide like chlorine. To 24 oz. of water add 1 tsp. of vinegar, 1 Tbs. of sugar and a crushed aspirin tablet.

Q:  What flowers can I plant on the south side of my house?  It’s a sunny, dry area.

A:  The following annuals should be fine on the south side as long as they get some water during the summer:  alyssum, celosia, cosmos, gazania, nasturtium, petunia, salvia and zinnia.

Q:  I have ants in the joints of our cement driveway and in the sand between the  bricks in the patio.  What can I do to control them?

A:  Use boric acid (a disinfectant available at pharmacies) as a tracking powder that is picked up on the legs of the ants and carried back to the nests.  This is a slow-acting insecticide and will take 10 days to 2 weeks to kill the ants.  It is relatively non-toxic but keep it away from children and pets.

Q:  There are round “bites” taken out of the leaves of my roses.  What is causing this?

A:  It sounds like leaf-cutter bees are eating your roses.  The bees rarely sting humans and are important pollinators of legumes and other garden plants.  The damage they do to the plants does not significantly affect the health of the rose bushes.  If you are exhibiting your roses you can cover the bushes with floating row covers.

Q:  What is Neem oil?  I’ve heard it is a safe, organic insecticide.

A:  Neem oil is a botanical extracted from the seeds of the neem tree.  The active ingredient azadirachtin acts as a growth regulator that interrupts the insect’s growth cycle causing death to larval and pupal stages.  It provides effective control for whiteflies, mealybugs, thrips, aphids, leaf miners and others.  It is also effective as a fungicide for control of foliar diseases like powdery mildew.  It can be toxic to bees if applied while bees are active.

Pinch back fall blooming plants such as asters and chrysanthemums to encourage branching and more flowers.  Continue to do this until mid-July.

Tender aquatic plants can go into outdoor ponds when the water temperature reaches 70 degrees.

Colorado potato beetles over winter in the adult stage and lay eggs in June.  Look for the egg masses on the underside of potato, eggplant, and tomato leaves.  San Diego and tenebrious strains of Bacillus thurengiensis can control young larvae.  In the home garden it is easy to hand pick adult beetles and crush larvae and eggs.  Our early warm temperatures may indicate a larger second crop of beetles.

Start a compost pile if you don’t have one.  Vines from early peas, tops cut from beets or carrots, vegetable scraps from the kitchen and grass clippings can all go into the pile.  Keep the pile moist (not soggy) during our hot weather and turn regularly.

The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.

Gardening and Insect Fact Sheets are available on-line by clicking HERE.

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This page updated:  March 13, 2003