Posted on by tonytomeo · 4 Comments

Knowing When To Prune What

Flowering plum trees can be pruned later, after bloom.

Maybe the weather took the surprise out of camellias this year. It has been so warm and pleasant that such big and colorful flowers are almost expected. Even if crocuses and narcissus did not bloom much too early, they are likely finishing a bit early because of the warmth and minimal humidity. Daffodils are not far behind. Hopefully, lilies and tulips will not be too confused. Pansies, primroses, stock, Icelandpoppies, ornamental cabbages and kales actually seem to enjoy the odd weather.

It was such a rush to prune everything that needs to be pruned in winter! Roses are already being outfitted with new foliage. Plum trees are already blooming, and will be followed by apricots, cherries, peaches and the rest. It was actually easy to get carried away, and prune things that should not yet be pruned.

Many of the flowering trees that are related to fruiting trees seem like they should be pruned. However, the rules are different, since they do not need to support the weight of fruit. Pruning only compromises bloom. Flowering cherries, flowering (purple leaf) plums and shrubby flowering quinces should instead be pruned after bloom finishes, and only if necessary. As flowering crabapples finish bloom, minor pruning probably will be necessary.

Lilacs, forsythias and spireas should be pruned by ‘alternating canes’, which means that older canes get cut to the ground as they get replaced by new canes. If done just after bloom, new canes develop through the following summer, and will be ready to bloom the following spring.

Quite a few trees, shrubs and vines likewise want specialized treatment. Fat flower buds of deciduous magnolias make it obvious that pruning should be delayed. Azaleas should probably make their intentions to bloom more obvious. Hydrangeas can be groomed of deteriorated flowers and dead stems, but plump canes from last year will bloom this year. Maples, birches and elms will continue to bleed if pruned now, so should wait for summer.

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Posted on by tonytomeo

Seasonal Pruning Is Precisely That

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Some trees get pruned after bloom.

Seasonal pruning is just as the terminology implies, seasonal. It might seem as if it all happens in winter. Most of it begins after cooling autumn weather initiates dormancy. Most of it is completed before warming spring weather stimulates vascular activity and resumption of growth. That is why most seasonal pruning is referred to simply as winter pruning. Winter really is best for most of it.

However, most is not all. Plants that are damaged by frost should not be pruned immediately. Because pruning removes insulating vegetation, and stimulates new growth that is more sensitive to frost, such pruning is delayed until after the threat of subsequent frost. Birches and perhaps maples are popularly pruned in late summer or autumn because they bleed so much if pruned in winter.

Flowering cherry, plum, peach, crabapple and quince do not need the same sort of pruning that their fruiting counterparts rely on. Their exquisite bloom is the priority, rather than fruit. Pruning prior to bloom could diminish their potential. They can instead be pruned immediately after bloom, as new growth is emerging, or later in summer after soft new growth has become a bit more resilient.

Lilac and forsythia should likewise be pruned after spring bloom, but more aggressively than the flowering fruitless ‘fruit’ trees. If not pruned enough, they will produce fewer canes through summer to bloom the following spring. Older and gnarlier canes should be cut to the ground to favor younger and less branched canes. Old Oregon grape and Heavenly bamboo canes can be culled too.

Redtwig dogwood and cultivars of willow that are pollarded or coppiced for their colorful twigs can be pruned later too. There is no need to deprive them of their primary assets prematurely. They should be pruned as winter ends though, before their buds start to pop. Pussy willow is an exception that gets harvested after buds have fuzzily popped, but before new growth begins to develop.

Evergreen plants can be pruned late in winter, just before new growth develops to replace what gets pruned away.