Colorado Master Gardeners - Arapahoe County

06/08/2026

Many large dead patches in the lawn this spring are a result of winter desiccation, lack of winter watering, pest damage, and disease. If adequate irrigation, aeration, and fertilization have been done this spring with no green up, it may be time to re-seed these lawn areas. See STEPS 6-8 at this link: https://extension.colostate.edu/resource/renovating-the-home-lawn/

06/04/2026

Annuals add beautiful color to the landscape. CSU Flower Trials annually evaluates a variety of plants to determine “the best of” for our unique environmental conditions. 2025 Best Of Annuals includes Salvia ‘Mystic Spires’, Calibrachoa ‘Double Grapefruit’, Begonia ‘Shine Bright White’, and Coleus ‘All That Lava’. https://flowertrials.colostate.edu/

06/01/2026

John Murgel, Douglas County Extension Specialist, offers information on the top 20 drought tolerant perennial flowers for Colorado. Read his article here:
https://engagement.source.colostate.edu/top-20-drought-tolerant-perennial-flowers-colorado/

05/29/2026

"There are 1006 native bee species in Colorado.... Unlike honeybees that are social and live in large colonies, 90% of native bee species found around the world are solitary. Approximately 70% of these bees nest underground in the soil, and about 30% nest inside hollow stems of plants and in pre-existing tunnels."

Read more about Colorado native bee populations:

https://extension.colostate.edu/resource/attracting-native-bees-to-your-landscape/

https://extension.colostate.edu/resource/creating-pollinator-habitat/

Of all the pollinators found in gardens, agricultural fields and natural areas, bees are the most common and efficient. There are over 20,000 bee species

05/27/2026

Creeping Thyme is in bloom, and the bees have noticed. Creeping Thyme is a popular ground cover throughout the United States. Read about thyme and ground cover plants:

https://planttalk.colostate.edu/topics/annuals-perennials/1063-thyme/

https://extension.psu.edu/herb-garden-plants-thyme

https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a294

https://lancaster.unl.edu/groundcovers-nebraska-landscapes/

05/21/2026

Master Gardeners receive many questions about turf grass. It can be one of our most popular topics. The first link is a great resource for basic lawn care. We've included additional links about mites and grass alternatives as well.

"The minimum height for any lawn is 2 inches. The preferred mowing height for all Colorado species is 2.5 to 3 inches. Mowing to less than 2 inches can result in decreased drought and heat tolerance and a higher incidence of insects, diseases, and weeds. Mow the lawn at the same height all year. There is no reason to mow the turf shorter in late fall." https://extension.colostate.edu/resource/lawn-care-basics/

https://extension.colostate.edu/resource/clover-and-other-mites-of-turfgrass/

https://planttalk.colostate.edu/topics/water-wise-xeriscape/1912-xeriscape-turf-alternatives/

Typical Kentucky bluegrass, the type of lawn most commonly grown here, grows best on 1.5” of supplemental water per week when the temperature is over 85 degrees. That means you will need to apply around an additional 15 inches of water a year to successfully grow your bluegrass lawn. Such use plac...

05/19/2026

Late spring is often a gamble when it comes to planting tender annuals, like nightshade (tomatoes). Since we have some cold weather right now, those of you growing tomatoes should understand that your plants might slow bud production or drop their flowers after the recent cold weather. This is normal. Learn more here:

"For optimal growing, tomatoes need warm temperatures: above 52ºF at night and above 60ºF during the day at transplant. They are readily killed by a light frost. A week of cool daytime temperatures (below 55ºF) will stunt plants, reducing yields. Soil temperatures are also important, soil temperatures must be above 55 ºF before transplant can be successful." https://extension.colostate.edu/resource/growing-tomatoes/

(Additionally, tomatoes don't like temperatures over 90F before noon. You will see the same decline in flower production and loss of buds in the hottest part of summer as well.)

Learn about growing tomatoes. From selecting varieties to planting, mulching, and more this guide will help you on your tomato growing journey.

05/14/2026

HALF PINT® pineleaf penstemon has red trumpet flowers that call hummingbirds and butterflies from June to August. A profusion of flowers bloom right above a tidy mound of soft, needle-shaped foliage. HALF PINT® prefers a little elbow room in the garden to provide it with maximum sun and heat. It's native to Arizona and New Mexico, so a small amount of gravel mulch will make this penstemon at home in the garden.

Plant Select is a partnership between Denver Botanic Gardens and Colorado State University.
https://plantselect.org/plant/penstemon-pinifolius-compactum/

05/12/2026

"Lilies also offer a wide range of flower colors, from pure white, pink, lavender, yellow, orange, red, burgundy, and multi-colored beauties. The species lilies are also quite pretty and interesting in their own right, with their varied flowers and growing habits. There are a few species of lilies that are native to the northern Great Plains region, making them well-suited for local gardens."

Lilies have long been a perennial staple of many gardens. They are prized for their large, showy, and often-fragrant flowers.