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Keep your landscape tip-top all year long.

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April

Trees and Shrubs

  • Plant trees, shrubs, and bare-root stock. Consider the design of your yard when choosing plants. Group plants with similar soil, light and water requirements. Visit a Colorado Nursery & Greenhouse Assoc. member for assistance with selections. Find a CNGA retail location near you.
  • Remove mulch around roses and prune dead or damaged canes.
  • Water shrubs and trees if the weather is warm and dry.

Flowers, Ground Covers, Perennials, and Ornamental Grasses 

  • Continue flowerbed cleanup and weed control as needed. 
  • Plant bare root perennials and transplant or divide summer and fall-blooming perennials like daylilies, asters, and fall anemones as they start to emerge.
  • Selectively prune or pinch late blooming perennials so they are full bodied later in the season.
  • Fertilize flowerbeds while plants are still dormant.  A slow release 5-10-5 fertilizer is generally recommended. Apply fertilizer in bands 3-4” away from the crowns of plants and scratch fertilizer into the soil with a rake or cultivator. Keep fertilizer granules off of foliage. A soil test will determine the level of organic matter levels of your soil. This will determine if you need fertilizer and if so what type.  
  • “Stake” or “cage” taller perennials, like peonies and delphiniums, as they emerge. Doing this before they start to flop avoids damaging them during staking. Many nurseries and garden centers have special cages for these perennials designed specifically to maintain their natural appearance. Visit a Colorado Nursery & Greenhouse Assoc. member for assistance with selections. Find a CNGA retail location near you.

Lawns 

  • Control weeds as needed.
  • Core-aerate lawn.
  • Check mower blades for sharpness and sharpen/replace as needed.
  • Depending on growth, begin regular mowing.
  • Re-seed or re-sod bare spots in the lawn.
  • If cool season turf is in poor condition fertilize at 0.5 – 1 pounds. Nitrogen/1,000 sq. ft and sod or over-seed thin areas. Water as needed based on current local watering guidelines and restrictions.
  • Precipitation is often at its highest in April and lawns need only about ¼” of water per week under normal circumstances. Delaying the start-up of your sprinkler system may save you money and conserve our most precious natural resource - water. Daily watering is only necessary with new seed or sod to help it establish. In all other circumstances daily watering only encourages shallow root growth and reduces the turf's drought tolerance.
  • As soon as your lawn reaches 3.5” high begin mowing; keep in mind ideal lawn height is 2.5” – 3”.  To encourage lawn health and strength, try not to remove more than 1/3 of the leaf blade at each mowing. In April and May this my mean mowing every 4-5 days. 

Vegetables

  • Control weeds as needed; pulling is a great option while they are small.
  • If you didn’t get this done in late March, plant cool-season vegetable crops, such as spinach, peas, carrots, lettuce, broccoli, cabbage, Swiss chard, kale, beets, carrots, radishes, radicchio, turnips and onion sets outdoors.
  • If you wish to start vegetables early, warm the soil with a Wall of Water, Kozy Cone, Hot Caps or Season Extenders for one week before planting warm season vegetables.

Miscellaneous

  • When you start your sprinkler system this spring consider upgrading your time clock to one with water saving features or installing a rain sensor or soil moisture sensors to help conserve water. Watch for runoff and avoid watering streets and sidewalks. Reducing your irrigation to just what the plant needs will save you money and helps prevent diseases. 
  • Celebrate Earth Day and Arbor Day by planting a tree or donating your time to an environmental event in your community.  



May

Trees and Shrubs

  • If needed, prune spring flowering shrubs such as lilacs and forsythia right after blooms have faded. Now is the time to prune these plants even if they did not flower.
  • Plant potted or balled-and-burlapped trees and shrubs. Consider the design of your yard when choosing plants. Group plants with similar soil, light and water requirements. Look for well-developed roots throughout the root ball and for an abundance of small white roots on the outside of the root ball.

Flowers, Ground Covers, Perennials, and Ornamental Grasses

  • Pinch dead flowers from spring-blooming bulbs, but leave the leaves until they “die back”, they provide food for next year's bulbs.
  • Plant annuals, patio containers, summer bulbs, such as gladiolus, lilies, dahlias, and cannas and vegetables after the danger of frost, generally between May 10th -15th. Consider planting a few bulbs (like lilies, dahlias, cannas, etc) underneath the annuals in your larger containers.
  • If you have not already done so stake taller perennials like peonies and delphiniums before they start to flop (See April tips). Visit a Colorado Nursery & Greenhouse Assoc. member for assistance with selections. Find a CNGA retail location near you.
  • Plant bare-root plants by mid-May.
  • Fertilize plants as needed.

Lawns

  • If you have not already done so aerate and fertilize your lawn.
  • Plant cool-season seed or sod turf grass. 
  • If the weather has been dry, water established bluegrass lawns deeply, about 1 inch once a week.  
  • If you have a Buffalo grass or other warm season turf lawn, late May or early June (right after the grass starts to green) is the time to fertilize. Fertilize at a rate of ½ to 1 lb. of nitrogen per 1,000 square feet. Un-irrigated Buffalo grass lawns may only require fertilization every other year if the clippings are returned to the lawn. Fertilize cool season turf once mid-May to mid-June with about 0.5 lbs. Nitrogen/1,000 sq. ft.
  • Mow weekly, or as needed, never removing more than 1/3 of the leaf blade. Mow at 2.5-3” height for maximum vigor and to conserve water. 

Vegetables

  • Plant vegetable starts outside after the danger of frost has passed. Warm season crops such as tomatoes, peppers, beans, squash, cucumbers and eggplant prefer a week of at least 50 degrees or above for night time temperatures before planting.
  • Fertilize vegetables as needed.

Miscellaneous

  • Start weeding when the plants are still small and do not have any seed heads.
  • Follow local watering guidelines and restrictions; watering only as needed.
  • Check sprinkler and drip systems and make adjustments as needed. Lawns need about 1” of precipitation per week, shrubs trees and flowers should thrive on about ½” to ¾” of precipitation per week. 
  • Take a break for inspiration. 
  • Stretch before doing a lot of yard work to prevent pulled muscles.
  • Visit your local botanical garden to see iris and other spring perennials in bloom. 
  • Attend local charity plant sales and visit a Colorado Nursery & Greenhouse Assoc. member for inspiration and assistance with selections. Find a CNGA retail location near you.



June

By June you've accomplished a lot, be sure and take a break for inspiration! Visit your local botanical garden to see the roses and perennials in bloom.  

Trees and Shrubs

  • Prune early flowering shrubs such as lilacs and forsythia after blooms have faded. 
  • Water trees and shrubs only as needed and remember to adhere to local water restrictions and guidelines. 
  • Visit a Colorado Nursery & Greenhouse Assoc. member for assistance with selections. Find a CNGA retail location near you.
  • Flowers, Ground Covers, Perennials, and Ornamental Grasses
  • Remove foliage from spring-blooming bulbs after leaves have completely died back.
  • Continue deadheading and weeding as needed. Deadhead or pinch back annual flowers to keep them bushy and full of blooms.

Lawns

  • Adjust your sprinkler so that established bluegrass lawns receive about 1 ½” of precipitation a week. Avoid water waste by monitoring how much water your sprinkler puts out and by setting your sprinkler to run in a way that avoids runoff away from the lawn.
  • Raise your mowing height on cool season turf lawns (like bluegrass) to 3” and continue to mow as needed removing only 1/3 of the blade at each mowing.
  • If you have a Buffalo grass or other warm season turf lawn, fertilize in late May or early June, right after the grass starts to green. Fertilize at a rate of ½ to 1 lb of nitrogen per 1,000 square feet. Un-irrigated Buffalo grass lawns may only require fertilization every other year if the clippings are returned to the lawn. 

Vegetables

  • It's a good idea to set out heat loving veggies like tomatoes, squash, pumpkins, cucumbers, and peppers when night temperatures are consistently above 50 degrees.
  • Remember to weed regularly.



July

Flowers, Ground Covers, Perennials, and Ornamental Grasses

  • Continue to deadhead and weed regularly.
  • Monitor all your plants for early signs of disease or pest infestation.
  • Divide bearded irises.

Lawns

  • Water your lawn as needed always following local watering guidelines and restrictions. It's a good idea to limit watering to high-visibility, high-impact areas.



August

DIY Pro-tip: If it has been 3-5 years since your last soil test, collect a soil sample and have it tested. The results should guide your compost applications and fertilization activities for the next 3-5 years. 

Trees and Shrubs

  • Fertilize your trees and shrubs in late July or early August at the rate of about 1 lbs. Nitrogen/1,000 sq. ft. If you’ve already fertilized your lawn or if your trees are drought stressed, skip fertilizing.
  • Start to cut back on watering your trees, shrubs, and perennials as this will help push them into dormancy and improve their survival.

DIY Pro-tip: A fertilizer with a ratio of 3-1-1 or 3-1-2 and a low salt index is generally recommended. Apply a light application of fertilizer starting 18” out from the trunk and fertilize to the drip line of the tree (or 10 ft. of radius for every 1” of trunk caliper at breast height). Scratch fertilizer into the soil and/or water heavily. Be sure to avoid late applications of fertilizer in order to help prevent hardening off issues.

Flowers, Ground Covers, Perennials, and Ornamental Grasses

  • Deadhead and weed as needed.
  • Fertilize your flowerbeds in late August at the rate of about 0.5 lbs. Nitrogen/1,000 sq. ft.

DIY Pro-tip: If weather isn’t too hot, A slow release 5-10-5 fertilizer is generally recommended. Apply fertilizer in bands 3-4” away from the crowns of plants and scratch fertilizer into the soil. Be sure to avoid getting fertilizer granules on your foliage. Don't fertilize if soil organic matter levels are above 5%. 

Lawns

  • Fertilize cool season turf in mid-August to mid-September with 0.5-1.0 lbs Nitrogen/1,000 sq. ft. If you have a sandy soil, make this your final fertilizer application for the year. 

Vegetables

  • Plant your cool-season crops now for a bountiful fall harvest in mid- to late August.



September

  • September is an ideal time to add to your landscape, by spring your new plants will be established and ready to thrive.
  • To prolong harvest this season, cover plants on cool nights.
  • Make a list of desired renovations and begin planning for next year.

Trees and Shrubs

  • To encourage dormancy and improve winter survival, begin limiting water.
  • Remove snow from all branches if there’s an early snowstorm.

Flowers, Ground Cover, Perennials, and Ornamental Grasses

  • Continue watering, weeding, and deadheading, as needed.
  • Divide early season perennials like Siberian Iris, Day Lilies, Peonies, and perennial beds to help ensure plants are well established and require less water during cooler months.
  • Remove plants that have proven to be too disease susceptible.
  • Plant spring bulbs like Daffodils, Tulips, Hyacinths, and Crocus.
  • Plant perennials in fall to help ensure establishment by spring.
  • Add fall and winter color with pansies.

Lawns

  • After a thorough watering or soaking rain, core-aerate your lawn.
  • Bring new life to your lawn by over-seeding or sodding thin areas.
  • For lawns in clay soil, September is the last time you should fertilize.

DIY Pro-tip: If you didn’t fertilize in August or the weather was too hot, apply 1.0 -1.5 lbs. Nitrogen/1,000 sq. ft. This is the most important fertilizer application of the year for turf on clay soils.



October

  • Winter is just around the corner, it’s time to complete your fall cleanup and set the stage for spring.
  • Turn off and drain your sprinkler system. When soil is dry, water by hand.
  • Keep your yard clear of leaves and yard debris; they can damage grass and vegetation.

Trees and Shrubs

  • As soil begins to cool, adding mulch helps prevent evaporation and helps control weed growth and erosion. Recommended mulches are bark or shredded leaves.
  • In the case of an early snowstorm be sure to remove snow from all branches.

Flowers, Ground Covers, Perennials, and Ornamental Grasses

  • Remove diseased plants and deadhead as needed.
  • Cut back perennials that don’t contribute to winter interest.
  • Tender bulbs like dahlias or gladioli will do best if they're dug up and stored for next season.
  • Plant spring bulbs as soon as they arrive. 
  • Rough spade your annual beds and then apply a light layer of compost to the bed.  This will help control pests and diseases, and allows compost to mellow over the winter.

Lawns

  • Continue to mow and water as needed. Use this time to prepare for the following growing season with a good winterizer fertilizer.

Vegetables

  • Rough spade annual and vegetable beds, follow with an application of compost.

DIY Pro-tip:  For new (1-3 year old) annual beds apply 1.5-2” of compost. For older beds (3+ years old) apply no more than 1” of compost per year.  For vegetable gardens use only approved non-bio-solid composts.



November - December

If the soil is dry and warm weather is expected for several days during November and December, it's a good idea to water your lawn and ground cover areas, pansies, and newly planted trees and shrubs once a month. Remember, most established trees do not need extra water except in very exposed conditions.

Trees and Shrubs

  • Mulch around roses after the cold weather sets in and plants have stopped growing. Recommended mulches include bark or shredded leaves. 
  • During any heavy snowstorms be sure to remove snow buildup from limbs and branches.
  • Wrap small and sensitive tree species once they are completely dormant.

Flowers, Ground Covers and Ornamental Grasses

  • Plant spring bulbs before the soil freezes.

January

  • Begin planning for changes you hope to make this year in the garden.
  • Research new varieties of favorite plants in seed catalogs and online. 
  • Stay inspired with greenery and color throughout the winter with an indoor container garden.
  • Take some cuttings of Forsythia and other early blooming shrubs and bring them indoors for forcing. 
  • Enjoy fresh herbs with an indoor herb garden; transfer plants outside in spring.



February 

Trees and Shrubs

  • By mid-month try to clean up leaves and other yard debris, weather permitting.
  • Check trees and shrubs for any maintenance pruning that may be necessary.  Concentrate on removing broken branches or branches that cross and may become damaged from rubbing.
  • Slow early growth and help conserve water by reapplying mulch that may have thinned. 
  • During heavy snowstorms remove snow buildup from limbs.
  • If conditions have been dry, water evergreens and newly planted deciduous trees and shrubs once this month. 
  • Water only if the soil is dry and only when warm weather is expected for several days. Most established deciduous trees do not need extra water except in very exposed sites. 

Flowers, Ground Covers, Perennials, and Ornamental Grasses 

  • If the weather is nice cut back perennials and grasses that were not cut back in the fall and add mulch to perennials beds to conserve water and slow early spring growth. 
  • If conditions have been dry, water perennial and ground cover beds especially if they are in areas not getting natural precipitation or under large mature trees. Water only if the soil is dry and only when warm weather is expected for several days.  

Lawns

  • If conditions have been dry water lawn areas especially if they are under large, mature trees. Water only if the soil is dry and only when warm weather is expected for several days.

DIY Pro-Tips: Make a list of damaged or missing tools – visit a Colorado Nursery & Greenhouse Association member for their suggestions on replacements. Find a CNGA retail location near you. Clean and sharpen other tools.

Visit the Colorado Home & Garden Show in Denver. It’s a great resource for gardening ideas and advice for the upcoming season.


March 

Trees and Shrubs

  • During heavy snowstorms remove snow buildup from limbs.  Prune any branches that are broken or heavily damaged.
  • If conditions have been dry, water lawn and ground cover areas, evergreens, and newly planted deciduous trees and shrubs once each month. Water only if the soil is dry and only when warm weather is expected for several days. Most established deciduous trees do not need extra water except in very exposed sites.
  • In late March or early April remove wrap from trees.  Be sure to remove any tape that was securing the wrap to the trees to avoid damaging the trunk as the trees grow.
  • Prune summer-blooming shrubs, those that bloom on the current season’s growth, in late March before new growth begins. (Examples: Blue Mist Spirea, summer-blooming Spirea, Butterfly Bush)


Flowers, Ground Covers, Perennials, and Ornamental Grasses

  • Cut back perennials and grasses that were not cut back in the fall.
  • Add mulch to perennials beds.

Lawns

  • If you didn’t core-aerate your lawn in fall, it can still be now depending upon the weather. 

Vegetables

  • Start annual and vegetable seeds indoors.  In late March peas, sweet peas, lettuce, broccoli, cabbage, kale, onion sets, cauliflower, radicchio, spinach, carrots, beets, radishes, turnips, and Swiss chard can be sown outdoors.
  • In late March or early April, rototill flower and vegetable beds. If you did not top-dress these beds with compost in October, do so now before rototilling (see October for instructions). Do not rototill when soil is either too wet or too dry. Ideally soil is similar to a moist, wrung-out sponge. 

DIY Pro-Tips: Start planning for the season by looking for bare spots in your garden that could benefit from the addition of trees or shrubs later in the season. Make a list for your first shopping spree. Visit a Colorado Nursery & Greenhouse Assoc. member for assistance with selections. Find a CNGA retail location near you.