Spring Clean-Up Advice for the Eco-friendly Gardener
The below average precipitation we've been experiencing this winter is likely to continue into the summer. Here are some tips for March to protect your soil and help make your garden and landscape ready for the growing season.
Check Your Drip System for Leaks
In a few weeks it will be safe to turn on your drip system. Light freezes typical in late March-April and early May will not cause damage to your drip system. Turn on each zone and walk your landscape to find any leaks or damaged tubing. This is very important because, once you apply the mulch so important for protecting soil moisture, it's very difficult to find leaks that waste precious water.
Feed the Soil
If you forgot to feed your soil last fall with an ample application of Yum Yum Mix, it's time to do now. Yum Yum Mix is an all natural fertilizer specifically formulated for our northern NM soils. My long term experience with this fertilizer has demonstrated that that it supports healthy living soils and provides the essential nutrients that make plants robust and resilient.
I like to spread it over the top of the soil and scratch it in with a hand cultivator or small stiff hand rake.
Water Deeply to Flush Yum Yum Mix onto the Soil Surface
Now, it's time to water in the Yum Yum Mix so that the soil organisms can start to digest the ingredients and break them down for the plants to utilize later in the spring. I like to use a sprinkler (on a calm, windless day) to moisten the ground and Yum Yum Mix.
After watering, cover the area with a good 1 to 2 inch thick layer of whatever mulch your using. By thickening up the mulch layer, this will insure that the sun and wind don't evaporate the moisture and leave it in the soil for the plants to use. This year, it will be essential to use more mulch, especially on younger, less established trees, shrubs and flower beds.
Training Your Landscape to be Less Thirsty
Many xeric (waterwise plants) require winter/spring moisture before conditions get hotter and drier in the summer. Good deep watering in March and April will provide these water thrifty plants with much needed moisture and store water in the soil for later in the spring.
In dry years, continue to water deeply to moisten the soil to a depth of one foot or so. But do it a little less frequently than you would in a normal year. This teaches the plants to grow just a little bit, but not lushly, as they would in a wet year. Applying more water than usual can cause the plants to grow lushly in late spring, only to require more water as conditions get hotter and drier moving into June and July.
Get Your Pruning Done Very Soon
Deciduous Shrubs and Trees: The time for hard pruning of shade, fruit, flowering trees and spring blooming shrubs has past once we reach the end of March. As a general rule of thumb, once the leaf and flower buds begin to swell, the primary pruning season is done.
Summer blooming shrubs like Russian Sage (Perovskia), Blue Mist Spirea (Caryopteris) and Butterfly Bush (Buddleia davidii and hybrids) can be cut back in mid-spring.
+ 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.
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 in mid-spring. Leave about 2 to 4 inches of stubble standing; big growers should be left with about 4" and smaller growers should be left with about 2".
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 that should not be cut to the ground. Instead vigorously "comb out" dead leaves with gloved hands and clip off the dead leaf tips. In early to mid-spring, clip off old seed head stalks as far down into the foliage as possible to leave room for late spring flowers.
Come late March/early 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 injure or kill these evergreens.
- Lavender (Lavandula) - to get these important ornamental herbs ready for the new growing season, I recommend waiting to cut them back until you can see tiny green stems beginning to push out from the old woody stems. This will show you how much of the old branches have been damaged from winter cold and desiccation. Shear the plants to remove the dead branches just above where the upmost new growth is emerging from the old stems, to leave a nice rounded mound of stems and foliage. Remove old dead foliage in the plant's interior by roughing them up the stems/leaves with gloved hands.
- Beardongue (Penstemon) - Cut back the old flowering stems and lanky stems to leave a nice mound, rounded mound of the evergreen leaves and stems. This will re-invigorate the plants and make the flowering stems more even.
- Other evergreen perennials - simply remove winter killed stem tips and foliage to leave a nice mounded plant.