Pruning Flowering Shrubs

Pruning the flowering shrubs in your landscape isn’t difficult if you understand these practical rules. Practical rule number one: prune spring flowering shrubs after they bloom and before they set seed. 

Spring blooming shrubs such as forsythia, lilac, ninebark and weigela already have this spring's flower buds in place. They're 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 a month after they stop blooming. 

Practical rule number 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”. Practical rule number three: don’t prune. If you’re uncertain about the blooming habits of the shrubs in your landscape, don’t prune until you’ve had time to observe each plant’s growth and bloom cycle. Then you can employ practical rule one or practical rule two, whichever is applicable. Practical rule number four: prune anytime there is a need to remove dead, damaged or diseased branches. It’s always the right time to remove any branches that pose a hazard. The shrub will recover over time. 

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.  

Prune Caryopteris back to about six inches, if you want to maintain the same height each year.

 If you want your Blue Mist spirea to increase in size each season, prune it back by one third now.  After you're done pruning, give your ornamental shrubs a good drink. Wait another month to feed your shrubs. When you do, select a fertilizer with a higher Phosphate formula, such as 11-15-11. 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 healthy and blooming for many seasons. 

Plant Smart with Plant Select®

In 1999, Colorado State University, in conjunction with Denver Botanical Gardens, landscape professionals and independent growers formed Plant Select®. The goal of this consortium is to provide a menu of grasses, perennials, trees and shrubs that will perform exceptionally well in our unique climate. In order to be accepted into the Plant Select® program, each candidate is subjected to a rigorous 7-point process including the ability to thrive under a broad range of conditions, demonstrate resistance to disease and insects and flourish with less water. 

Over the last twenty years, over 130 plants have met the criteria and been elected to Plant Select® including Dog Tuff™ grass, Hyssop and Winecups.  Each of these perennials, shrubs and trees will enhance your landscape while optimizing water requirements. 

Many perennials will attract pollinators to your garden. On Saturday February 23, 2019 at 1 pm, Ross Shrigley, the Executive Director of Plant Select® will be conducting a class on how to incorporate Plant Select® perennials and shrubs into your existing landscape. For more information, visit The Flower Bin events page: https://www.theflowerbin.net/home-decor.  

Plant Select® also publishes a handy guide to plants pamphlet and maintains an informative website:  https://plantselect.org/.  Shop with confidence when you see the Plant Select® sign, knowing the perennial, grass, shrub or tree you choose will meet your expectations for drought tolerance, low maintenance and performance. 

Now's the Time for Dormant Oil

Starting in late summer, aphids, mites and scale begin preparing for winter by laying eggs on the trunks and branches of fruit-bearing and ornamental trees in your landscape. These eggs will remain in place until spring temperatures reach a hatching point. Throughout the winter, small holes on the surface of the eggs allow air into the developing insect inside. It is the breathability characteristic of these insect eggs that allows dormant oil to be effective this time of year. The dormant oil coats the insect egg, cutting off the air flow. 

Dormant oils are made from highly refined mineral oils.  Product choices include concentrated Ferti-Lome Dormant Spray and ready-to-use Ferti-Lome Horticultural Oil Spray. 

If you want the convenience of a product that's ready to use, choose Ferti-Lome's Horticultural Oil Spray. Hook up the hose, turn it on and you're ready to spray. For larger jobs, it's more cost effective to buy Ferti-Lome Dormant Spray. Dormant Spray can be applied with a tank sprayer or a hose end sprayer. 

For ease of application, buy a self-mixing hose end applicator. You set the dial to the recommended rate either tablespoons or teaspoons, hook up the hose and the sprayer mixes the right proportion automatically.  There's no waste because you don't have to guess at how much spray you need. When you're done, unhook the hose, disconnect the sprayer, put the cap back on the container and store it on the shelf. Ideal conditions for spraying dormant oil would be on a day in late February or early March when the temperature is above 40°F, there’s little or no wind and no rain or snow in the forecast. Plan to spray early in the morning so the tree or shrub will be dry by evening. Spray enough to cover the tree trunks and shrub branches thoroughly. 

Dormant oil may be applied every two weeks up until bud break; the point when the bud starts to show color. While dormant oil reduces the insect stress on ornamental trees and shrubs, it’s your fruit trees that will benefit the most. 

 Spraying your fruit trees now will increase the overall yield as well as the quality of the fruit you harvest. Photo Credit Monrovia. In addition, applying dormant oil now reduces the need for more aggressive insecticides later in the season. 

February Tree Care Tips

Now’s the ideal time to prune, while the trees in your landscape are still dormant. Regular maintenance is important to your tree’s health and longevity, but sometimes it’s difficult to know where to start the pruning process.  That’s when pruning at this time of year, or dormant pruning offers many advantages. Pruning opportunities express themselves more readily due to a lack of leaf cover. 

Begin by noting any obvious problems such as broken, dead and damaged limbs. Look for branches that are crowding or rubbing together, branches growing straight up or straight down and any water shoots emerging from the base of the tree. 

Using a sharp pair of bypass pruners or loppers, cut cleanly at the branch collar. Next, look for any evidence of disease. In the spring of 2018, we experienced an extensive outbreak of fire blight. Many ornamental and orchard trees were affected, including apple, pear, mountain ash and crabapple. 

Once started, it can be a challenge to control fire blight. The most effective approach is a combination of good cultural practices, pruning and the application of topical controls. If your trees exhibited these symptoms, now’s the time to prune out the affected branches. Because the disease is dormant at this time, there is no need to disinfect your pruners between cuts.  Plan to make your pruning cut eight to ten inches below the infected tips. It’s important to avoid removing more than twenty five percent of the tree at any one time. 

For heavily infected trees, this means leaving some blighted branches intact. As soon as the tree sets blossom in the spring, spray with a fire blight control. 

Choose a mild, dry day to do your pruning. Proceed slowly. Don’t try to make up for years of neglect. Pruning, like anything else, gets easier with practice and done consistently, represents a significant influence on the heath of your trees.