Garden Tips for April 🌼
Spring, with its unpredictable weather is here. Many of us are at home with a lot more time on our hands because we're not working. Use this pause to get reacquainted with our gardens and landscapes and take vital mental nourishment from our efforts. Get your irrigation system ready, cut back your plants to remove the dead foliage from last year’s growing season and prune your summer blooming shrubs. It’s also time for soil care; feed the soil and mulch. And keep an eye out for critters that want to make your yard their person cafeteria.
This is going to be a great planting season. And it's worth remembering that the best time to refurbish an existing xeriscape or plant a new one is when water is available after a good snow year.
Now that it's April, it's time to cut back our perennials
If you haven't already done so, cut off dead, above-ground stems and leaves. In general, these perennials will show you where to cut. Look for a low mound of new foliage at the base of the old dead stems and cut off these dead brown stems just above the new green foliage.
It's best to wait until mid-spring to cut grasses back. There are two categories of grasses; cool season and warm season growers. They are handled differently during spring clean-up.
Warm season grasses include Little Bluestem (Schizachyrium), Big Bluestem (Andropogon), 'Blonde Ambition' Blue Grama (Bouteloua), Muhly (Muhlenbergia), Prairie Switchgrass (Panicum), Chinese Maidenhair Grass (Miscanthus), Giant Sacatoon (Sporobolus wrightii) and others. They should be cut back hard in mid-spring. Big growers should be left with about 4" of stubble and smaller growers should be left with about 2" of stubble. It's essential that the old stems be roughed out with gloved hands to remove dead stems from the crown and leave room for new foliage to emerge.
Cool season grasses, like Blue Avena Grass (Helictotrichon), Fescue grass (Festuca), Silky thread Grass (Nassella) and 'Karl Foerster' Feather Reed grass (Calamagrostis) have evergreen foliage. But I’ve noticed that this cold winter has damaged the foliage of these grasses freezing them back nearly to the ground. So go ahead and cut them back to green foliage. But mound the cut; no flat tops.
Get Your Garden Clean-up Done in April
Deciduous Shrubs and Trees: If these plants are blooming or starting to leaf-out, The time for hard pruning of shade, fruit, flowering trees and spring blooming shrubs has passed. As a general rule of thumb, once the leaf and flower buds begin to swell, the primary pruning season is done.
Summer blooming shrubs
Native Salvia ( Raspberry Delight, 'Furman's Red, 'Maraschine' and other S. greggii and microphylla types) have started to push new foliage from their woody stems. Remove all wood above the new foliage and shape the plants into a dome. Also thin out interior branches to clean up the lower main stems. Top-dress the soil around your newly pruned plants with some compost and Yum Yum Mix. I mix 1 part Yum Yum to 2 parts compost. This will provide essential nutrients for them to grow back vigorously and bloom plentifully.
Lavender (Lavandula) – I've cut my lavender back hard this year, removing the top 1/3 to 1/2 of the plants. Also top-dress your lavender plants like the Salvia above.
Rosemary should be cut back to remove winter killed branch tips. Also prune into a dome shape and thin interior branches along the main stems. What a wonderfully fragrant task!
Russian Sage should be cut back hard in mid-spring, leaving stems 12-15" tall. This should be done every spring to keep them blooming heavily. This is also the time to dig "suckers" (new stems to push up from the ground) so to keep your Russian sage in bounds and not overtaking its neighbors.
Blue Mist Spirea and Buddleia davidii should be cut back by 1/3 to 1/2 of their height every third year (NOT annually) to re-invigorate the shrubs and encourage blooming.
Check your landscape, to see if you see a flush of young green grass sprouting up under Rabbit Brush (Chamisa) bushes, elms and other shady/partially shady areas. Most likely, this is Cheat Grass (Bromus tectorum), a highly invasive non-native grass from western Asia that has overtaken the western US. It's an annual grass that goes to seed in May and dies by late June. But it leaves behind showy but horrible seed heads that can puncture the skin and penetrate the eardrums of our pets causing great damage and pain. This plant is also highly flammable and creates extreme fire danger once the grass dies leaving behind lots of biomass (seed heads and dead foliage).
There are good natural herbicides, like Phydura Weed Killer Spray, Burnout II that use non-toxic plant extracts and oils or make your own homemade recipe*, to burn back and kill annual weeds. Spray the young cheatgrass plants on a warm, sunny day in April to kill them before the go to seed. If you miss killing the young seedlings, mow or weed-wack the grass just as the seed heads ripen in late May. Eliminating a fresh crop of seeds is important to do every year to control this awful weed.
*Homebrew herbicide recipe: 1 gal. cooking/cleaning vinegar + 2 cups Epsom salts + ¼ cup liquid dish soap (Dawn, Ivory or Dr. Bronners). Apply I a spray bottle directly to the green grass.
Turn On and Check Your Drip System for Leaks
By late April, it's time to turn on your drip system. Late, light freezes possible through the middle of May will not cause damage to your drip system. Turn on each zone and walk your landscape to find any leaks or damaged tubing. Gophers love to chew through the pipes and can cause major leaks. Do the walk-through before you apply fresh mulch as it's very difficult to find leaks when the emitters and tubing are covered.
Keep Watering New Spring Transplants Deeply Every Couple of Weeks
Keep up with the regular watering of young trees, shrubs, vines and perennials for at least 2 or 3 growing seasons. Under-watering younger woody plants will stunt their growth. Even xeric native trees and shrubs will make better landscape specimens with regular watering to get them well established and larger in size. Then watering frequency can be decreased over the following years.
If watering by hand, be sure to re-build their wells (small mounds of soil that ring the base of the plant to hold water). Then fill the well a couple of times to soak the soil deeply.
The general rule of thumb when it comes to watering is Water deeply but less frequently so the roots will follow the water down more deeply into the soil. Shallow, frequent watering encourages shallow roots.
Feed the Soil Before Mulching
Spread the mulching material to make a good 1 to 2-inch thick layer. By thickening up the mulch layer, this will ensure that the sun and wind don't evaporate the moisture and leave it in the soil for the plants to use. Also helps to control weeds and slowly enrich the soil.
Don’t forget to replenish your gravel mulch. After a cold winter like the 2018-19 season, the freezing and thawing of the soil pulls the gravel into the soil and thins the gravel depth on the surface.
Mulching fruit trees heavily will help to keep the soil colder and delay early flowering somewhat. It also helps to control grass around the tree which eliminates grass root competition and increases the tree’s growth.
Gophers have always been a problem in northern NM. But the mild winters of the past 5 or so years seem to have allowed them to increase their populations. And they are especially active in the spring. So, it’s critical that you protect both new transplants and established plants from getting their roots eaten.
New transplants – sprinkle a handful of Chase Mole and Gopher Med granules around the base of each plant at planting time and soak the ground to move the emulsified castor oil into the soil.
Established plants – watch for mounds of fresh soil and treat the area with the Mole and Gopher Med. Water in thoroughly.
New transplants, even rabbit-resistant species like Penstemon and Salvia should be sprayed with a deer/rabbit repellent at planting time. Repeat one more time until the plants start to grow new foliage.
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