April and May are busy months for gardeners. What you get done in the next 60 days will set the stage for outdoor summer enjoyment and home-grown meals.
USING HOOP HOUSES FOR FROST PROTECTION
If you planted bare-root roses or have already transplanted cool-season vegetable starts, you’ll want to cover them as cold weather and below-freezing nights loom for April 2-4. Most established plants will take this frost, rain and snow and just keep rolling, but newly planted pansies or new small fruits might be vulnerable.
Cover these plants with fabric, burlap, floating row cover or whatever you’ve got – just don’t let plastic touch them, because that transmits the freezing cold right through to tender new leaves.
Cover any just-about-to-bloom tulip beds with cardboard boxes, plastic tubs or old laundry baskets, then with a fabric sheet or plastic if you don’t want them crushed.
And check out the hoop system tutorial in the DPTV videos (denverpost.com/dptv). It’s an easy, inexpensive framework that helps support covers to shield crops from for cold temperatures, wind or hail, insect or birds and even high heat.
LAWNS
• You can start mowing your lawn in April when turf reaches around 3½ inches tall. But make sure you start the season with sharpened blades, fresh gasoline and oil, a clean air filter and spark plugs. Get the wheels, axles and bearings in good working order. Tune it yourself or take to a reputable service shop — and do it now, before the May rush.
• Reel or push lawn mowers also benefit from yearly tuning and sharpening.
• Gone electric? Good for you. Sharpen the blades, check cords for nicks or cuts (replace if inner wires are severed,) and clean the air vent slots and the carbon blocks. For cordless electric mowers, take the mower for a test run to ensure the battery didn’t die over winter.
• Only in Colorado can lawns suffer from due to long periods of snow cover (February), then weeks later be subject to in dry conditions. Inspect your lawn for both. More: and
• There’s no need to fertilize yet, especially if the lawn was fertilized late last fall. Fertilization now will lead to fast growth and you’ll just need to mow more often.
• Use pre-emergent products if grassy weeds have been a problem. Hand-dig dandelions and other broad-leaf weeds. Horticultural vinegar (that’s 20 percent acetic acid, sold in garden centers) is good for spot treating. Try placing a toilet-paper roll over the weed, then spraying into the roll.
• Core aeration can be done anytime in April or May, as long as it’s before it gets too hot, so make your appointment now. Aerate a day or two after the lawn has received moisture so that longer, deeper plugs of soil are pulled. Aeration does the best job to relieve soils that have become lumpy from earthworms or compacted by foot traffic and heavy use.
• Before your aerator arrives, flag sprinkler heads and any shallow electrical or irrigation lines to prevent damage. Plan to overseed spare areas with grass seed, fertilize and water right after aeration — those holes are perfect little germination chambers — unless, of course, you’ve used a pre-emergent.
•Criss-cross the area several times so the plugs are pulled at two-inch intervals. The holes left by the plugs open up space for air, water and fertilizer to reach and benefit the root zone of your lawn
• Aeration is better than power raking to battle and keep thatch in check. Thatch is a mixture of grass stems and roots that do not break down quickly and form a layer preventing water and nutrients reaching turf roots. You can leave the plugs of soil on the lawn or toss in the compost pile, your choice.
• Aerating around the base of trees is beneficial to tree roots.
IN THE LANDSCAPE
• Until it’s safe to turn on the sprinkler system (late April into May), you’ll need to drag hoses and deeply water the landscape unless it rains.
• Cut back spent foliage on most perennial herbs and late-summer and fall-blooming shrubs and plants. The shrubs to cut back now include blue mist spireas, butterfly bushes, Russian sage and ornamental grasses. But don’t remove the new growth of spring or early-summer bloomers. And wait to cut back perennial lavender, thyme and sages until later, when the plants are up and growing. They generally need only a light pruning of about a third of the plant to shape them.
• Don’t prune roses until late April or May, even if you see new growth on the canes. Too-early pruning can lead to new growth that easily gets damaged by frosty nights.
• Stake taller or wider perennials whose heavy blooms may flop — peonies are in this group — now or in the next few weeks.
• Remove tree wrap on trees.
• Plant hardened-off pansies outdoors
• Plant hardy annual seeds outside, including sweet peas (soak them overnight first), larkspur and bachelor buttons.
• Clean the bird feeders, refill them and give birds fresh water.
• Stake out and prepare any new planting beds. Plan to attract wildlife or put in a water-wise garden, rock garden, ornamentals, fruits or vegetables. Consider raised beds, containers or trellises for tight spaces. Search for advice on planning all types of gardens at colostate.edu/pubs/LandscapeDesign.html
FOOD GARDENS
Edible perennials may seem counterintuitive, but there are food plants that live longer than two seasons. They require that you choose their locations carefully.
• such as raspberries, grapes, strawberries, currants, gooseberries and jostaberries, elderberries and serviceberries). More: cmg.colostate.edu/pubs/SmallFruit.html
• Most of these plants need eight hours of sun daily, a site that’s away from competing tree roots and easy access to water. Good soil conditions don’t hurt, either. Garden centers now have fresh perennial starts and canes ready to plant.
• Annual cool-season vegetable tubers, sets or cloves can be planted outdoors in April, including potatoes, onions, shallots, and garlic. You can also transplant broccoli, cabbage, cauliflower and Brussels sprouts (just keep your frost protection handy for nights under 45 degrees). It’s also time to direct-seed leafy vegetables (lettuce, spinach, kale, arugula) and peas, radishes, turnips, parsnips, carrots, onions, broccoli rabe, kohlrabi, and beets.
• Indoors, you can start seeds of tomatoes, peppers, eggplant, tomatillo and okra for transplanting out in the garden in mid- to late May.
• Finish pruning cane fruits including blackberries, raspberries and grapes.
• as the new growth appears, but keep it close to use when frost threatens and to keep fruit off the ground once it begins appearing. More: www. ext.colostate.edu/pubs/garden/07000.html
• Wait to transplant or direct-seed annual and perennial herbs until May.
Betty Cahill: gardenpunchlist.blogspot.com
