The Spring Pruning Routine
It’s that time of year! The sun is growing stronger, the snow is melting, and spring bulbs are starting to peak up out of the soil here and there. For some of the woody members of your garden, this is the best time of year to do a bit of spring cleaning and prune to improve their health, help them live longer, and improve yields of certain fruits. However, for others this is one of the worst times of year to prune. Join us as we sort out the basics of spring pruning and talk about commonly grown plants that should and should not be spring pruned.
The Basics of Spring Pruning
The main idea behind spring pruning is to remove dead or winter damaged growth, unshapely branches, or extra buds to produce a better-looking form that will allow for growth throughout the season. It is also a time to take advantage of the fact that many species are still sleeping and will not bleed too much when pruned. Keeping up with pruning small amounts yearly leaves less large wounds than doing large prunes every few years which reduces the chance of rot and disease. Here is and outline of the three main types of pruning involved in spring pruning.
The Types of Spring Pruning
Pruning For Shape/Size involves reducing or pruning branches to get a desired shape, or to keep a potentially large plant in check. Remember to make cuts above buds and to cut above a outward facing bud to avoid the new growth coming in at awkward angles.
Pruning to Thin is used for species that bite off more than they can chew when it comes to new growth. This helps open up the structure of the plant to allow room for new growth and for proper air flow to avoid fungal diseases. With too much growth some plants can become crowded or fail to fruit or flower properly. This is also useful technique in foliage species like dogwood where foliage on older growth may sparse and not be as attractive.
Pruning To Restore is a more intense form of thinning that deserves its own category. Essentially, large amounts of old wood are removed to allow for new growth to take place. Sometimes this is done at the expense of fruit or flowering in the coming season. It should be used sparingly and works best for plants that fruit or flower on new growth.
The Best Plants to Spring Prune
The plants that benefit most from a good spring prune are those that produce flowers or fruits on new growth or that may produce too many buds to properly yield fruit. Common shrubs that bloom on new growth in the summer and benefit greatly from spring pruning are potentillas, spireas (not bridal wreath spirea), most shrub roses and butterfly bush. Any shrub grown primarily for the foliage such as ninebarks, ,cotoneasters, junipers, barberries and boxwoods can also benefit from a light spring pruning. Some plants may require a slightly later spring pruning after dormancy is required so that you can tell what is dead or not. This is really helpful for plants like Rose of Sharon which often have tip dieback in the winter and it is hard to tell which buds are strong.
Grapes are an example of something that produces an excess of buds and will fruit poorly if not pruned to thin before it starts putting effort into all those extra buds and branches. Grapes only fruit on the second year growth so each fruiting stem should be reduced to two or three buds so that two strong fruiting vines are grown instead of many weak ones. Any shoots that are being left to extend the structure of the trunk can be left but the strongest ones should be chosen to do so.
Many foliage vines such as Virginia creeper, engleman ivy, and Boston ivy can also be spring pruned while they are still dormant to clean them up. Weak growth is removed and unwanted branches can be pruned back to a set of buds. Trumpet vines can also be kept in check by reducing the length of side branches to a couple strong buds. Weaker clematis growths can also be shortened and those that bloom on new growth can be cut back hard to strong buds. Hops vines grow from the roots every year so if they were not cleaned up in the fall they should be in the spring.
Ramblers like blackberries can also benefit from the shortening of the new growth to 24” to make them more manageable and promote strong fruit spurs. Primal cane raspberries fruit on one year growth and can be trimmed back hard. Normal raspberries should only have the dead canes removed. Younger highbush blueberry bushes benefit from spring tip pruning to promote strong branching and an open form and as the plants get older, removing scraggly older branches that aren’t fruiting well will increase productivity. Shortening of the fruiting, two-year old growth can also help avoid overproduction which can lead to smaller berries and the plant becoming exhausted and skipping fruiting the next year.
Spring Pruning Don’ts
There are certain plants that should not be spring pruned, this is because they either flower or produce fruit on the second years growth or do not produce excess growth that needs to be removed. Check and make sure if your plant your thinking of pruning is on this list below!
Many of the plants on the list of don’ts for spring pruning are fruiting plants. This includes apples, pears, quince, and any stone fruits like peaches, plums, cherries, apricots and nectarines. These fruits should only be summer pruned. The exception is removing the extra, thin year-old growth known as water suckers from apples and pears which can take energy away from the fruiting branches. Vigorous cherry and peach varieties may also need the shortening or thinning of the largest branches to promote strong fruiting and prevent damage from extra fruit weight. It is best to consult a pruning guide for your variety in this case.
In addition to fruits, there are some flowering plants that should not be spring pruned. Most mophead and oakleaf hydrangeas also flower on second year growth only and should not be pruned until after flowering. Some exceptions are the Annabelle and limelight varieties. Lilacs, forsythias, climbing roses and weigelas are summer flowering but bloom on older wood so they should only be pruned after flowering. One third to one half of the length of old growth (two or more years) of these may however be removed in the spring to help rejuvenate restore and rejuvenate the plant as discussed above.
Properly Pruning Conifers
Some shrubby conifers can benefit from a light spring pruning but there are a couple rules that must be followed. Rule one: never prune a conifer back past active buds, most will not res-prout from brown wood. Rule two: the growing parts of longer needled varieties like pines are best “candled” instead of pruned. This is done in early summer when the tips are growing. Simply break off the largest of the fuzzy tips at the growing point to promote bushiness and branching. This can also be done with trees like dwarf spruce that grow long sprouts at the top. Rule three: Don’t prune too hard, less is more with conifers and too heavy of pruning can shock the plants.