CNGA Monthly Lawn Care and Gardening Checklist

Cold temperatures and snow in January usually mean frozen ground, and not a lot opportunity to work with your lawn. This is the ideal time of year to look at your yard and start to make plans for the Spring and Summer.

You should attend local garden and home shows for ideas and advice on gardening for the upcoming season. Look for the CNGA booth at the Colorado Home & Garden Show held at the Colorado Convention Center every year.

Though February often has the same cold weather as January, it’s the best month to start work on your yard for the coming season. Maintenance on plants and planters in your yard in February will prepare them for the Spring, and will help to deter early growth. Colorado’s usual late frosts can stunt the growth of trees, shrubs, and even grass if they start their Spring growth too early.

Warming in March means more preparation for the coming season. Trees and Shrubs can be uncovered and pruned, and vegetables can be seeded indoors. Much of the work you do in March will help to set up your yard with a consistent level of health.

Lawn and Miscellaneous Tasks

• Core aerate lawn.

• Start annual and vegetable seeds indoors. Peas and sweet peas can be sown outdoors.
• Start planning for the season by looking for bare spots in your garden that could benefit from the addition of trees or shrubs in later in the season. Make a list for you first lawn shopping spree.

Flowers, Ground Covers, and Ornamental Grasses

• Cut back perennials and grasses that were not cut back in the fall.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.

• Add mulch to perennials beds.

Trees and Shrubs

• Remove snow build up from limbs during heavy snow storms.

• 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 will not need extra water except in very exposed sites.

• In late March or early April, remove wrap from trees.

• Prune summer blooming shrubs (those that bloom on the current season’s growth) in late March.

• Remove winter wrap from newly planted trees.

April is when maintenance on your yard can start to become a little more consistent. Warmer temperatures and growth mean you can uncover and/or plant trees and shrubs. You should inspect your lawn mower to ensure its blades are sharp, as you may find yourself performing the year’s first mow in April.

Special Dates in April: Earth day is April 22nd, and Arbor Day is usually the last Friday of April. Celebrate these age-old holidays by planting a new tree or donating your time to an environmental event in your city.

Below you’ll find CNGA’s list of recommended tasks for April:

Lawn and Miscellaneous Tasks

• Weed control as needed.

• Core aerate lawn.

• Re‐ seed or re‐ sod bare spots in the lawn.

• Check mower blades for sharpness and sharpen/replace as needed.

• Begin mowing lawn to a height of 2.5‐3” as soon as it reaches 3.5”. Mow frequently enough as to never remove more than 1/3 of the leaf blade at each mowing (this may be every 4‐5 days in April and May).

• When you start up your sprinkler system this spring consider upgrading with water saving features like rain or soil moisture sensors. Reducing your irrigation to just what the plant needs will save you money and will help prevent diseases in your plants and lawn.

Fertilization and Precipitation

If cool season turf is in poor condition fertilize at 0.5 – 1 lbs. Nitrogen/1000 sq. ft and sod or over‐seed thin areas. Water as needed, following local watering guidelines and restrictions. Precipitation is often at its highest in April, and lawns need only about .[uh?]” 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.

Flowers, Ground Covers, and Ornamental Grasses

• Continue flower bed clean‐up and control weeds as needed.
• Remove mulch around roses and prune dead or damaged canes.
• 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.

• “Stake”/”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.

Fertilization

Fertilize flower beds while plants are still dormant. Fertilize at the rate of about 0.5 lbs. Nitrogen/1000 sq. ft. 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. Do not fertilize if soil organic matter levels are above 5%.

Trees and Shrubs

• Plant trees, shrubs, and bare‐ root stock.

• If weather is warm and dry, water shrubs and trees.

Vegetables

• Control weed as needed (pulling is a great option while they are small).
• Plant cool‐season vegetable crops, such as spinach, peas, carrots, lettuce, chard, kale, beets, carrots, radishes, turnips and onion sets 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 (like a moist, wrung‐out sponge is ideal).

Though February often has the same cold weather as January, it’s the best month to start work on your yard for the coming season. Maintenance on plants and planters in your yard in February will prepare them for the Spring, and will help to deter early growth. Colorado’s usual late frosts can stunt the growth of trees, shrubs, and even grass if they start their Spring growth too early.

Special Dates in May: The average last spring frost for the Colorado Front Range is May 8th.

Below you’ll find CNGA’s list of recommended tasks for February

Lawn and Miscellaneous Tasks

• Aerate (if you have not already done so) and fertilize lawn.

• Plant cool‐season seed or sod turfgrass.

• Water established bluegrass lawns deeply, about 1 inch once a week, if the weather has been dry.

• 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 1000 square feet. Unirrigated 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/1000 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 water conservation.

• Start weeding when the plants are still small and do not have any seed heads.

• Water as needed, following local watering guidelines and restrictions.

• 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 1/2” to 3/4” of precipitation per week.

• Fertilize flowers and vegetables as needed.

• Take a break for inspiration.

• Visit your local botanical garden to see iris and other spring perennials in bloom.

• Attend local charity plant sales and visit your local independent nursery or garden center for advice and inspiration.

Flowers, Ground Covers, and Ornamental Grasses

• Pinch dead flowers from spring‐blooming bulbs, but leave the leaves until they “die back” because they provide food for next year’s bulbs.
• Plant annuals and vegetables after the danger of frost. Plant summer bulbs, such as gladiolus, lilies, dahlias, and cannas.
• Plant Patio containers.
• 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).
• Plant bare‐root plants by mid‐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 because of an unseasonal freeze this year. 

• Plant potted or balled‐and‐burlapped trees and shrubs.

Vegetables

• Plant vegetables starting after the danger of frost has passed

June means Summer is in full swing!

Below you’ll find CNGA’s list of recommended tasks for June

Lawn and Miscellaneous Tasks

• Adjust your sprinkler so that established bluegrass lawns receive about 1-1/2” 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 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, late May or early June (right after the grass starts to green) is the time to fertilize. Fertilize at a rate of 1/2 to 1 lb. of nitrogen per 1000 square feet. Unirrigated Buffalo grass lawns may only require fertilization every other year if the clippings are returned to the lawn.
• Monitor all plants for early signs of disease or pest infestation.
• Take a break for inspiration.
• Visit your local botanical garden to see roses and perennials in bloom.

Flowers, Ground Covers, and Ornamental Grasses

• Remove foliage from spring‐blooming bulbs after leaves have completely died back.
• Continue dead heading and weeding as needed. Deadhead or pinch back annual flowers to keep them bushy and full of blooms.

Trees and Shrubs

• Prune early flowering shrubs, such as lilacs and forsythia, after blooms have faded.

• Prune evergreens, if needed.

• Water as needed.

Vegetables

• Set out heat loving veggies like tomatoes and peppers when night time temperatures are consistently above 50 degrees.
• Weed on a regular basis.

Below you’ll find CNGA’s list of recommended tasks for July

Lawn and Miscellaneous Tasks

• Water as needed, following local watering guidelines and restrictions

Flowers, Ground Covers, and Ornamental Grasses

• Continue dead heading, weeding, and disease/pest monitoring.
• Divide bearded irises.

The height of the Summer in Colorado also means its time to start thinking about the winter. This is when cool-season crops can be planted outdoors for a harvest in the fall. The amount of water your trees and shrubs receive should be slowly lessened to prepare them for dormancy over the winter.

Below you’ll find CNGA’s list of recommended tasks for August

Lawn and Miscellaneous Tasks

• Fertilize cool season turf in mid‐August to mid‐September with 0.5‐1.0 lbs Nitrogen/1000 sq. ft. If yours is a sandy soil, this should be your final fertilizer application for the year, so don’t skip this application.
• 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.

Flowers, Ground Covers, and Ornamental Grasses

• Dead head, and weed as needed.
• Fertilize flower beds in late August at the rate of about 0.5 lbs. Nitrogen/1000 sq. ft. 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. Keep fertilizer granules off of foliage. Do not fertilize if soil organic matter levels are above 5%.

Trees and Shrubs

• Fertilize trees and shrubs in late August at the rate of about 1 lbs. Nitrogen/1000 sq. ft.
  • Do not fertilize trees in lawns if you have already fertilized the lawn.
  • Do not fertilize drought-stressed trees.
  • A fertilizer with a ratio of 3‐1‐1 or 3‐1‐2 and a low salt index is generally recommended. Apply 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.
• Start to cut back on watering of trees, shrubs, and perennials. This will help push them into dormancy and will improve survival

Vegetables

• Sow cool-season crops for fall harvest.

September is no stranger to snowfall in Colorado. Even a warm September should be spent focusing on preparing your yard for next year. Continue preparing plants for dormancy, start to seed perennials and thin grass, and apply fertilizer.

Below you’ll find CNGA’s list of recommended tasks for September:

Lawn and Miscellaneous Tasks

• Core‐aerate the cool season turf lawns unless they are severely drought stressed and cannot be irrigated.
• Over‐seed or sod thin areas of cool season turf.
• If yours is a clay soil, late September is the last time you will fertilize your cool season turf. Apply 1.0 ‐1.5 lbs. Nitrogen/1000 sq. ft. This is the most important fertilizer application of the year for turf on clay soils, so DO NOT skip it!

Flowers, Ground Covers, and Ornamental Grasses

• Continue watering, weeding, and dead heading, as needed.
• In late August or early September, divide early season perennials, Siberian iris, daylilies, and peonies. Plant perennial beds in late August and early September. This will assure good establishment and use less water to do so.
• Remove and discard plants that have proven to be too disease susceptible.

Trees and Shrubs

• Start to cut back on watering of trees, shrubs, and perennials. This will help push them into dormancy and will improve survival.
• Remove snow build up from branches of trees and shrubs in the event of an early heavy snow fall.

Vegetables

• Start a list of yard renovations you’d like to make next year.

If it hasn’t already happened, you can always count on October for the year’s first snow and first frost. This means your yard needs winterizing to endure the cold. Winterization includes protecting plants from the elements, blowing-out sprinklers, and adding top-layers of compost to beds and planters.

Special Dates in October: The average first frost for the Colorado Front Range is in early October.

Below you’ll find CNGA’s list of recommended tasks for October

Lawn and Miscellaneous Tasks

• Mow and water as needed
• Turn off and drain sprinkler system. After this, water by hand if soil is dry.
• Clean up leaves and yard debris.

Flowers, Ground Covers, and Ornamental Grasses

• Remove diseased plants/dead head as needed.
• Cut back perennials that don’t contribute to winter interest.
• Dig up tender bulbs like dahlias or gladioli and store for next season.
• Add mulch where needed.
• Rough spade annual beds and then apply a light layer of compost to the bed. This will make soil preparation in the spring a breeze, will help control pests and diseases, and will allow compost to mellow over the winter. 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.
• Plant spring bulbs as soon as they arrive.

Trees and Shrubs

• Add mulch where needed.
• Remove snow build up from branches of trees and shrubs in the event of an early heavy snow fall.

Vegetables

• Rough spade annual and vegetable beds, apply a much of compost now. Apply 1.5‐2” of compost in newly constructed bed (years 1‐3) and no more than 1” of compost in established bed (3+ years old). For vegetable gardens use only approved non‐biosolid composts.
• Rough spade vegetable beds and then apply a light layer of NON‐biosolids compost to the bed. This will make soil preparation in the spring a breeze, will help control pests and diseases and will allow compost to mellow over the winter. 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.

These cold months will have your plants in dormancy, needing only protection from the elements and occasional water. During storms, sensitive plants should have extra protection, and all plants should have snow build-up removed after storms.

Below you’ll find CNGA’s list of recommended tasks for November and December:

Lawn and Miscellaneous Tasks

• Water lawn and ground cover areas, and newly planted trees and shrubs once per month (if the soil is dry and warm weather is expected for several days). Most established trees do not need extra water except in very exposed conditions.

Flowers, Ground Covers, and Ornamental Grasses

• Plant Spring bulbs before the soil freezes.

Trees & Shrubs

• Mulch around roses after cold weather sets in and plants have stopped growing.
• Remove snow build up from limbs during heavy snow storms.
• Wrap small and sensitive tree species once they are completely dormant.