By Rhiannon Allen
Is it spring yet? What a late start this year! Yet spring is inevitable, and the weather is warm enough to start spring tasks as the garden awakens from its slumber. Aside from weeding and cleanup, most garden tasks for April involve woody shrubs. In Pacific Northwest gardens, the common ones are forsythia, spirea, rhododendrons and that star of the summer garden: roses.
Speaking of forsythia, this is a must-have shrub for every neighborhood. Various cultivars brighten the garden with their cheery yellow flowers anywhere from February through April.
While forsythia does not provide much gardening interest once its flowers have faded, it serves as a vital alarm clock for gardeners. Are its flowers starting to open? Then it is time to attend to the other shrubs in your garden, especially the ones that you should have trimmed in January or February.
By trimming, I mean removing some branches before the shrub leafs out so much that you won’t be able to see what needs attention. One example is wisteria, from which side shoots should be removed before the plant starts its summer growth spurt. Rhododendrons, in contrast, only need obviously dead branches cut back to the collar where they join larger ones.
Other shrubs include spirea, potentilla and osier dogwood. Use the rule of thirds for these. Either remove one-third of the stems as close to the ground as you can (taking out the largest, oldest ones), or shear the entire shrub of its top third of growth. The aim here is to foster an attractive plant by either opening it up or keeping it compact.
Even if you lose some of this year’s blooms by removing branches, the plant will pay you back with its increased ornamental value, looking less choked up or rambunctious as a result of its spring trimming.
By the way, these tasks are ideally completed in January while the plants are dormant, but the weather then was so unpleasant that we did not want to spend time outdoors wrestling unruly wet branches. April is just really the last chance to get this done before the mid-spring growth spurt that these plants will be putting on.
Do you have roses in your garden? Then the forsythia’s blooms are also your signal to prepare them for summer. Head out with your thick garden gloves and pruners. Any obviously dead or frost-killed wood has to go.
Roses can also be pruned for size and shape. The aim for most ornamental roses is to foster an open, vase-like shape that will provide good air circulation that will keep black spot in check. Remove branches that cross or touch other branches because these can rub and abrade each other in the breeze, leaving the plant open to infection.
Following good pruning principles, use a sharpened pruner to cut cleanly at the collar that joins smaller to larger branches. Cut at a slight angle if possible, so that rain will run right off the cut you make, rather than pool on the cut and provide a good breeding ground for pathogens.
Not sure of the ideal place to cut a long cane? Just make sure that you cut above a bud that faces the outside of the plant. Otherwise, you will encourage branches that cross the interior of the shrub and rub other branches.
When you’re cleaning up the prunings, be sure to gather up any rose leaves lying around, because they probably have black spot spores just waiting for the warm temperature and rains to facilitate their growth.
While you’re trimming and pruning, you have probably noticed lots of swelling leaf buds on your shrubs. Now’s the time to give those shrubs that food boost they will need for healthy growth. If you don’t mind a lot of hand watering, liquid fish fertilizer diluted in a watering can will supply a well-rounded organic fertilizer that most plants appreciate.
While you’re at it, give your hellebores and other spring-blooming plants a treat because they will appreciate the food after the effort of blooming. Fish fertilizer is a bit stinky, but spring rains will dilute its odor as they wash it into the ground. That aroma will be a distant memory by the time you are lounging outside among your lush and appreciative plants.
In addition to the fish fertilizer (or specialty rose fertilizer), roses appreciate a handful of Epsom salts around their base. Epsom salts provide magnesium and sulphur that help leaf growth and function.
All done? Not quite. Remember that forsythia? By now it might have finished blooming. To ensure a healthy, well-mannered, blossom-filled shrub next year, grab your loppers and cut out the oldest one-third of the canes, removing them right down to just above the soil line.
Now done? Yes, but summer is on its way!