April Gardening Tips for the Mountain West and High Plains
Spring has sprung! It's time to roll up the sleeves, get outdoors, and spend time in the landscape with these timely April gardening tips.
Trim your grocery budget this year by growing your own vegetables. Follow these tips to know what to plant when in your garden.
Higher Elevations and Coldest Northern regions: Plant seeds or seedlings of cool-season crops including radish, pea, lettuce, and greens. For broccoli, cauliflower, and cabbage, plant seedlings only.
Lower Elevations and Warmer regions: Your last average frost date is this month. Check with a local garden center if you're unsure the correct date. When danger of frost is past, plant seedlings of warm-season vegetables and herbs, like tomatoes, peppers, eggplants, and basil.
For all elevations and regions: Plant potatoes and perennial vegetables, such as rhubarb, strawberry, and asparagus.
Wait two to three weeks before sowing seeds of heat-loving varieties such as corn, squash, green beans, cucumbers, and melons. (This also includes heat-loving flowers, such as zinnia, marigolds, and cosmos.)
Test Garden Tip: You know soil is warm enough (60F) for heat-loving crops when you can walk on it barefoot. This temperature typically occurs about two weeks after your last average frost date.
Remove winter protective mulch as soon as you spot perennial shoots poking through soil.
Clip remaining dead stems from last year's growth. If rabbits attack your garden in spring, leave 3- to 4-inch stem stubs to protect new growth.
Cut back ornamental grasses before their new growth starts. For large clumps, gather stems into a bundle with a bungee cord and cut with electric hedge clippers.
Dig and divide perennials that flower in summer or fall. If you're unsure if you need to divide, ask yourself these questions:
Are clumps too big for the space they're occupying?
Has flower number dwindled over the last growing season (or two)?
Does the clump have a dead spot in the middle surrounded by a ring of growth?
Do you want more plants of that type?
What NOT to Divide
Wait to divide spring bloomers following their flower show. Otherwise, they won't bloom this year.
Divide bearded iris in late summer. Aim to have divisions in the ground by Labor Day.
Divide peonies in early fall -- if at all. The main reason to divide these is because plants aren't growing well, you want to increase your patch, the growing spot has become too shady, or you're sharing divisions with a friend. Otherwise, the rule of thumb is that peonies need divided every 150 years.
After Bulbs Bloom
Remove spent flowers on spring-blooming bulbs, like daffodils and hyacinth. Don't clip leaves; let them age naturally before removing. Leaves generate food reserves to fuel next year's flower show.
Allow species tulips to set seed. This encourages clumps to spread.
Finish pruning trees and shrubs -- except for spring bloomers. Prune these immediately after flowering. Prune evergreens from now until late summer.
Prune roses once red leaf buds have swelled and just barely started to unfurl. Make cuts to shape bushes and to remove dead stems. Cut floribundas, grandifloras, and hybrid teas back to about 6 inches tall.
Fertilize roses. Choose from two methods: Liquid fertilizer: Apply every two weeks until August. Slow-release fertilizer: Work into soil around roses every 6 weeks. Compost: Work a spade of compost into soil around roses monthly.
Some rose fertilizers include a pesticide, which allows you to feed plants and fight pests at the same time. Read the label carefully. These products also kill beneficial insects and butterflies
Bare-root trees, shrubs, and roses can still go in the ground this month. You can also tuck container-grown trees, shrubs, groundcovers, and perennial herbs and flowers into beds as long as you're no more than a month away from your last average frost date.
Fill pots with bloomers that thrive in early spring's cool nights. Choices include pansy, viola, flowering stock, sweet alyssum, snapdragon, and calendula.
Test Garden Tip: As soon as soil is workable in spring, you can dig in. Not sure if soil is ready? Grab a handful and squeeze. If it stays clumped together, it's too wet for digging. If it crumbles apart like a piece of moist cake, grab your trowel and shovel.
If you haven't already, get your mower ready to go this month. Change the air filter, replace oil and spark plugs, and sharpen the blade. Add fresh gas, and you're ready to go.
At lower elevations, when forsythia blooms, apply crabgrass preventer. It works by preventing seeds from germinating, so don't apply if you plan to seed bare patches. If you do apply crabgrass preventer, seed bare patches in fall.
Aerate your lawn in spring, before seeding or fertilizing (if you're doing those things). Typically, you want to aerate every two or three years to reduce compaction and thatch. Rent a machine that removes plugs of soil or have a lawn service do it. You can also aerate in fall.
Bluegrass, ryegrass, fescue, wheatgrass: Mow to a height of 2-3 inches.
Buffalograss and blue grama: Mow to 2-3 inches or leave unmowed.