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Now is the Time for Perennials   arrow

Sally Weisser
Colorado State University Extension Master Gardener in Larimer County
June 13, 2015


Perennials are the mainstay of gardens everywhere and now is the perfect time to plant them. They are rewarding to grow, and unlike annuals, they return every year. They come in all shapes, sizes, colors with various foliage textures and colors. With some planning you can have beautiful color from spring into fall with some winter interest. Perennials can be planted anytime that the threat of frost has passed and a month before the first hard frost in the fall. Now is a perfect time to plant perennials into the landscape. Planting in May and June allows the plants to become well established before winter.

After you have chosen the site for your new perennial plantings, there are a number of things that must be considered before you begin planting. If this is a new bed, then you should check your soil for the need for soil amendments. Most Colorado soil will need organic amendment like compost, peat, and aged manure. The next step is plant selection. Decide on a color scheme. Pastels are cool and calming while bold colors can pop a landscape. Repeating a color in your landscape can pull your landscape together and add continuity. Some homeowners like to bring their inside house colors to the outside to have a complete palate of colors. Monochromatic landscapes can also have a big effect. Let your imagination and creativity be your guide.

In considering plant selection, check the tag for valuable information. Make sure the plant is hardy for your area. Generally the Fort Collins area is Zone 4, which has a minimum temperature of -20 F to -30 F. It is also helpful to choose plants that thrive in your region. Plant Select® is a collaborative program between Colorado State University, Denver Botanic Gardens and The Green Industry of Colorado designed to seek and distribute the very best plants for Colorado and can be a valuable resource in your plant selection.

Another consideration is light exposure. A bed that is in full sun will get at least six hours of sun a day; a bed that receives part sun/part shade need at least four hours of direct sun a day. Light shade is the shade provided by a building or tree. Medium shade is under a tree that allows some light in and dark shade is under a dense tree that receives very little light. Your perennial planting bed may have one of these light exposures or a combination. Be sure to select the right plant for the right light exposure to ensure that the plant thrives.

Plants should be grouped into areas with the same irrigation requirements. Perennial beds usually need a separate irrigation system from the lawn irrigation system. A drip system or soaker hoses can supply a slow timed released amount of water. Organic mulch applied after planting will help maintain moisture in the soil longer and decrease watering times.

The plant tag will also tell you the bloom time of your plant. Choose plants that bloom in spring, some that bloom in the summer and some that bloom in the fall to have continuous color throughout the growing season. Also consider adding perennial grasses, flowering or evergreen shrubs, or trees to add texture and winter beauty to your landscape. Deadheading spent blooms on a regular basis can extend the bloom time of your plants. Plants that are deadheaded will continue to bloom through its season.

Be sure to consider the mature size of your plant when choosing plants for your landscape. The plant tag will describe the height and the width of the plant when it is fully grown. Be sure to space the plants according to mature size when placing them into the landscape. When you are selecting plants for your landscape, be sure to choose happy healthy plants. Avoid plants that are limp, spotted, have holes in the leaves, or have insects on them. If the plant is root bound, loosen the roots by scoring with a knife. Do not select plants with significant root issues.

Once your plants are in the ground and mulched, they should be fairly low maintenance. New plants will need to be watered more often than well-established plants. Keep your beds weed free so that your perennial roots are not competing with weeds for water and nutrients. Also consider garden art to enhance your perennial garden. A well placed birdbath, bird feeder, or garden chair can enhance the beauty of your garden. Enjoy your new area! For more information, refer to Plant Talk scripts #1072 and #1602 and Fact Sheet #7.405.


The author has received training through Colorado State University Extension’s Master Gardener program and is a Master Gardener volunteer for Larimer County.


Larimer County is a county-based outreach of Colorado State University Extension providing information you can trust to deal with current issues in agriculture, horticulture, nutrition and food safety, 4-H, small acreage, money management and parenting. For more information about CSU Extension in Larimer County, call (970) 498-6000 or visit


Looking for additional gardening information? Check out the CSU Extension Horticulture Agent blog at for timely updates about gardening around the state.


Visit PlantTalk Colorado ™ for fast answers to your gardening questions! PlantTalk is a cooperation between Colorado State University Extension, GreenCo and Denver Botanic Gardens.