- The Xeric Gardner | David Salman
Get Busy Now, Garden Tips for April 🌼
Spring is here. And that means it’s time to pull out your garden gloves and get your garden and landscape ready for the spring planting season. 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. Spring officially arrived this year on March 20 which coincided with a full moon. Look around at the prairie, the foothills and the mountains. After years of drought, you can see the energy and vitality of spring returning to the grasses, shrubs and trees with the generally abundant winter moisture. So take advantage of deep soil moisture to re-invigorate your xeriscape with new plants.
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
It’s been a wonderfully moist winter, the best in nearly a decade. So no watering of large, established plants are needed at this point. But remember to water new transplants regularly, even xeric species, to keep them growing and rooting through the growing season. This is especially important during the dry months of May and June.
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
The long drought from which we are enjoying a welcome reprieve has a hidden consequence. Prolonged lack of soil moisture impacts the soil ecosystem damaging the health of the soil’s microfauna (mycorrhizal fungi and other beneficial organisms) that break down organic materials that fall on the ground. By feeding the soil with Yum Yum Mix and compost, you can rebuild the soil’s health and improve plant growth.
I also recommend spreading mycorrhizal inoculants (Plant Success available from highcountrygardens.com) to increase micorrhizal populations that are essential to plant health.
Spread a Yum Yum Mix / high-quality compost blend onto the soil’s surface before spreading the mulch.
April is a good time to thicken up your existing mulch or cover new areas.
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.
Control Gophers
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 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.
Hungry Rabbits
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.
Control Noxious Cheat Grass Now !!!
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, that use non-toxic plant extracts and oils to burn back and kill annual weeds. Check local nurseries or go online to locate these herbicides. Spray the young Cheat grass plants 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.
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
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.
Flowering Vines
Vines should not be forgotten when doing your spring clean-up.
Silverlace vine (Polygonum aubertii), a large spreading species should be cut back now. This can be an aggressive vine that will grow into neighboring trees and shrubs. If left unchecked, they will grow over, strangle and shade out their neighbors. So remove Silverlace branches that have grown onto other plants.
Hummingbird Trumpet (Campsis) should be cut back as needed. This vine blooms on new growth, so it’s best to do any pruning now. There is no particular technique for this vine. Just shape it to fit its space and be sure it’s not overgrowing its companions. Look for any seedlings or suckers and remove them.
Hall’s Japanese Honeysuckle is indestructible and can be cut back hard to keep it restrained.
Grapes should be pruned in April. The NM State Cooperative Extension service has excellent online information on how to prune grapes.
Ornamental Grasses
Mid-spring marks the time to cut them back. 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.
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.
Now that it's April, it's time to cut back our perennials
Herbaceous perennials that have 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.
Evergreen perennials like Lavender, Rosemary, Beardtongue (Penstemon) and others, only need to have winter killed stem tips and leaves removed. Don't cut back evergreens to ground-level like their herbaceous neighbors. This will severally injure or kill these evergreens.
Lavender (Lavandula) – After a string of warm dry winters, this cold wet one seems to have knocked back the lavender plants around Santa Fe. I recommend cutting them back by about 1/3 to stimulate strong new re-growth for spring. This will also result in more flower spikes too. Cut out any dead branches at ground level and clean old dead foliage on the plant's interior branches by roughing them up the stems with gloved hands.
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