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Flower Management in a Dry Climate |
By Dr. Jim Klett, Larry Vickerman, and Carl Wilson, Colorado State University Cooperative Extension, Horticulture
| No Current Watering Restrictions |
| If Watering Restrictions are Expected in the Next Few Weeks or Mild Restrictions are in Place |
| When NO Watering is Allowed |
| After Watering Prohibition is Lifted |
No current watering restrictions:
The following practices will help keep your flowers healthy while conserving water.
Proper soil preparation prior to planting will help conserve water.
- Prepare soil before planting by loosening soil to 12 inches. If it is a heavy clay or sandy soil, add 2-3 inches of compost on the soil surface and then till in to a 12-inch depth.
Proper Mulch
- Apply 1-2 inches of organic mulch between flowers to reduce evaporation and control water-using weeds.
Fertilization
- Fertilizing perennials is generally not needed if proper soil preparation is done prior to planting. Fertilizer causes lush growth that requires more water. If fertilization is needed, a slow release fertilizer can be applied in the spring.
- Moderate fertilization for bedding plants is recommended either as liquid or granular or a combination of both.
Irrigation
- Annual and perennial flowers under water stress will have drooping leaves and a lack of blooms. Foliage often appears gray-green in color. Water when signs of stress become obvious. Apply irrigation in the evening or early morning to minimize evaporation.
- Overhead spray irrigation is the least water wise method as much water is lost to evaporation and wind drift. Soaker hoses or drip irrigation are more efficient because they deliver water to the ground level near roots. Hand watering is another alternative that maximizes delivery of water to the soil and roots.
Plant Selection
- Some perennials are more efficient at utilizing water than others. Choose your plants to match the site conditions.
- Gray-leaved annuals and perennials are often more drought tolerant. Spring bulbs are drought avoiders as they complete their life cycle prior to the onset of hot weather.
Click on highlighted names for photos and/or information on each plant:
Some Drought Tolerant Annuals |
Some Drought Tolerant Perennials |
| Annual fountain grass (Pennisetum setaceum) | Artemisias (Artemisia species) |
| Bachelor Button (Centaurea cyanus) | Blanket flower (Gaillardia x grandiflora) |
| Cockscomb (Celosia plumosa) | Blue fescue (Festuca cinerea) |
| Coreopsis (Coreopsis tinctoria) | Creeping phlox (Phlox subulata) |
| Cosmos (Cosmos sulphureus) | Creeping potentilla (Potentilla neumanniana) |
| Creeping zinnia (Sanvitalia procumbens) | German Statice (Goniolimon tataricum) |
| Cup Flower (Nierembergia hippomanica var. violacea) | Globe Thistle (Echinops ritro) |
| Dusty miller (Senecio cineraria) | Hens and Chicks (Sempervivum tectorum) |
| Gazania (Gazania rigens) | Ice plant (Delosperma species) |
| Globe amaranth (Gomphrena globosa) | Lambs ear (Stachys byzantina) |
| Johnny-jump-up (Viola tricolor) | Lavender cotton (Santolina chamaecyparissus) |
| Mealy cup sage (Salvia farinacea) | Little bluestem (Schizachyrium scoparium) |
| Mexican sunflower (Tithonia rotundifolia) | Oriental Poppy (Papaver orientale) |
| Moss rose (Portulaca grandiflora) | Ozark primrose (Oenothera missouriensis) |
| Periwinkle (Catharanthus roseus) | Penstemon (Penstemon species) |
| Rocket Larkspur (Consolida ambigua) | Plumbago (Ceratostigma plumbaginoides) |
| Rudbeckia (Rudbeckia hirta var. pulcherrima) | Poppy mallow (Callirhoe involucrata) |
| Spider flower (Cleome hassleriana) | Prairie coneflower (Ratibida columnifera) |
| Sweet alyssum (Lobularia maritima) | Prairie dropseed (Sporobolus heterolepsis) |
| Purple coneflower - (Echinacea purpurea) | |
| Russian sage (Perovskia atriplicifolia) | |
| Snow-in-summer (Cerastium tomentosum) | |
| Stonecrop (Sedum species) | |
| Yarrow (Achillea species) |
When
watering restrictions are expected in the next few weeks or mild restrictions are in
place:
- Annuals can be watered 2-3 times per week if approximately 1 inch of water is applied during each irrigation cycle.
- Water perennials deeply (1 inch of water or more) 2 times per week during hot, dry periods. Water in the evenings or early morning to prevent evaporation loss.
- Mulching both annuals and perennials is critical to prevent moisture loss.
When no watering is allowed:
- Do not plant annuals when outside watering is not allowed.
- Do not plant new perennials and mulch existing plants.
After watering prohibition is lifted:
- Some perennials may not survive extended drought.
- Resume watering and check for signs of new growth that should appear in several weeks.
- Water perennials well in the fall and monthly during dry winters with no snow cover to ensure survival during the dormant season. Mulching the crowns of dormant perennials will prevent frost heaving and conserve moisture in the plant through the winter.
Photo of flower bed with soaker hose: Judy Sedbrook
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