Spring Garden Chores

If you’re familiar with the adage “March comes in like a lamb and goes out like a lion” you’ll appreciate the general unpredictability of our March weather. March arrived this year with a high of 35°F and wind and snow forecasted off and on, then bounced close to 60° mid-month. That’s why as gardeners, eager to get going, it’s important to keep an eye on the forecast, start slowly and be prepared for changes in the weather. 

Begin gradually by removing any vegetation and debris left from last season. It’s important to proceed carefully because as you’re cleaning up, you’ll discover many perennials and bulbs are starting to show. The remains of last year’s garden acts as a mulch, protecting early spring risers such as crocus, hyacinths, daffodils and tulips.

Go gently around these bulbs and perennials, because it’s easy to damage them. You may want to switch from a leaf rake to a leaf blower or better yet simply clean up by hand. It’s important to leave some cover to protect these tender shoots through the rest of the spring. Stay off those areas of the garden that are wet, to avoid compacting the garden soil any more than necessary.  

 

As you're cleaning, you may find evidence of beneficial insect activity like this mantis egg sac. It's important to leave the nest undisturbed so it has a chance to hatch naturally in the spring.   

 

Now’s the time to evaluate the soil in your vegetable beds. Soil texture and richness are fundamental to your vegetable garden’s success and testing is something that should be done on a regular basis. Whether you’ve experienced specific problems, such as Tomato Blossom End Rot or you’ve been disappointed in your garden’s overall yields, it’s important to establish a baseline, to know how to proceed to improve your soil.

You can do this yourself with a simple test kit. Colorado State University Soil Testing lab has moved to: 

Soil, Water, and Plant Testing Lab 
4817 National Western Dr. 
Denver, CO 8021 

Soil, Water and Plant Testing Laboratory - Soil Testing Lab (colostate.edu) 

 

Once you’ve received your test results, bring the report in. We’ll help you choose the products you need to implement the changes they recommend. Foundational to soil quality and health is the practice of adding organic materials, called amendments. Effective soil amendments for the soil in our area include compost, peat moss and earthworm castings, but before you try digging in your garden make sure the ground is workable.  

 

Those areas exposed to the sun should be workable now. More shaded parts of the garden are still too wet to work. A simple way to do this is to grab a handful of soil and squeeze it. If it crumbles when you open your hand the soil is workable. If it stays in a clump, the soil is too wet, and you need to wait.  

 

In your perennial gardens, now is the time to prune back ornamental grasses. They do best if you cut them down to five or six inches above the ground.  

 

Summer flowering shrubs such as Buddleia and Bluebeard should also be pruned now. Wait to prune spring blooming shrubs such as Lilac, Forsythia, Spirea until after they bloom.  

 

This is also the time to prune Group 3 Clematis. These varieties bloom on new wood in late June into August. They should be cut back to a living bud at about 24" from the ground in spring just as the buds begin to swell. If you don't prune, the flowers will tend to be only up at the top of the plant and the bare stems will be unattractive below. When to prune Clematis can be tricky depending on the bloom time and variety.  

 

If you’re not sure, don’t prune.  If you’re uncertain about the blooming habits of the shrubs and vines in your landscape, don’t prune until you’ve had time to observe each plant’s growth and bloom cycle. Hold off pruning your roses until mid-April.  

         

Watch for perennial weeds that may have wintered over. Groundsel, Mallow and others can survive the harshest winter weather, and many are blooming right now. Dig them up or treat them with weed control.  

 

Now’s the time to do dormant spraying. Dormant spraying involves applying a preventative spray in late winter while fruit trees, deciduous trees and ornamental shrubs are still dormant.  The “dormant” part of “dormant oil” describes the timing of the oil’s application, rather than the type of oil.  Also called horticultural oil, the active ingredient in dormant oil is mineral oil. Applied now, this oil suffocates scale, aphids, mites, and other insects wintering over, reducing insect activity later in the growing season.  

 

Starting your clean up now will mean a more productive gardening season.   

   

Spring Pruning Flowering Shrubs and Vine

 

Pruning ornamental shrubs and vines is done to improve plant health and vigor, control size and shape, to increase flower production, as well as remove overcrowded, damaged stems and branches. Pruning should be part of the regular maintenance and upkeep of your garden. March is the right time to prune many of the shrubs and climbers in your landscape. Pruning these flowering shrubs and vines isn’t difficult if you understand these general rules. General rule number one: prune spring flowering shrubs after they bloom and before they set seed.

Spring blooming shrubs such as lilac, ninebark and weigela already have this spring's flower buds in place. These shrubs are said to bloom on “old wood” because soon after flowering last season, they began to set the buds for this season's blooms. If you prune these shrubs now, you'll remove most of the flower buds. The time to prune ornamental shrubs that flower in spring and early summer is within two weeks after they stop blooming.

General rule two: prune summer flowering shrubs such as butterfly bush, blue mist spirea and hardy hibiscus in late winter or early spring, because they bloom on this year’s growth or “new wood”. Now’s the time to prune summer flowering shrubs.

Summer flowering hardy hibiscus and butterfly bushes do best if you cut them hard to the ground now. You can use a lopper to cut the larger canes.  If you want your Blue Mist spirea to increase in size each season, prune it back by one third now.

This is also the time to prune Group 3 Clematis. These varieties bloom on new wood in late June into August. They should be cut back to a living bud at about 24" from the ground in spring just as the buds begin to swell. If you don't prune, the flowers will tend to be only up at the top of the plant and the bare stems will be unattractive below. When to prune Clematis can be tricky depending on the bloom time and variety. If you’re not sure, don’t prune.

General rule number three: Don’t prune. If you’re uncertain about the blooming habits of the shrubs and vines in your landscape, don’t prune until you’ve had time to observe each plant’s growth and bloom cycle. Then you can employ general rule one or general rule two, whichever is applicable.

General rule number four: prune anytime there is a need to remove dead, damaged or diseased branches. When it comes to the health of trees, shrubs and vines in your landscape, it’s always the right time to prune.   After you're done pruning, give your ornamental shrubs and vines a good drink. If you have questions about pruning in general or how to prune a particular shrub, stop by our Diagnostic Center. We'll help you figure out what to do to keep your shrubs and vines healthy and blooming for many seasons.