Pruning Deciduous Shrubs

Right now is the right time to prune some (not all) shrubs in your garden.

The first group of targets for pruning in April included flowering shrubs that bloom in the spring on old wood. These plants should be pruned soon after their blooms have faded. This practice allows ample time for buds to develop and bloom in the following spring. Pruning long after the blooms have faded will remove buds as they develop, and reduce or eliminate blooming next year.

Fading Lilac Bloom

The accompany photo shows fading blooms of a Common Lilac (Syringa vulgaris ‘White Angel’) in my garden. This is one of the Descanso Hybrids, which were developed in southern California for mild winter regions, like the Monterey Bay area. Unlike the lilacs from my youth in Connecticut, these hybrids bloom without a winter chill. This plant bloomed nicely and produced a fine fragrance, and now needs pruning in preparation for next year’s flowering.

Here are examples of additional plants in this group that grow well in the Monterey Bay area.

  • Flowering Quince Chaenomeles speciosa)
  • Forsythia (F. ovata and other species)
  • Japanese Rose (Kerria japonica)
  • Lily-of-the-Valley Shrub (Pieris japonica)
  • Mock Orange (Philadelphus lewisii and other species)
  • Ninebark (Physocarpus opulifolius and other species)
  • Purple-leaf Sand Cherry (Prunus × cistena)
  • Viburnum (V. tinus ‘Compactum’ and other species)
  • Weigela (W. florida and hybrids)
  • Winter Daphne (D. odora)

You can identify additional plants in this group by direct observation. If you are undecided, look up your plant in Sunset’s Western Garden Book, the American Horticultural Society’s A-Z Encyclopedia of Garden Plants, or a pruning reference book. You can also search for the plant on the Internet, ideally by botanical name.

Some gardeners are reluctant to prune their plants, either because of uncertainty or a fear of damaging the plant. It can be helpful to regard pruning as therapy for the plant, i.e., it helps and does not hurt the plant.

Pruning improves the plant first by removing dead, broken or diseased twigs and branches. Such parts of the plant are not good for the plant, and could be harming it by spreading disease or drawing resources.

Other benefits are beneficial primarily for the gardener. Timely pruning will improve flowering, fruiting, and overall shape. Flowering shrubs growing without the care of gardeners or landscapers will develop a pleasing natural habit entirely on their own. They will also produce enough flowers and fruit to reproduce, and enough roots and branches to ensure healthy growth. With this in mind, always prune for specific objectives. Before picking up the clippers, take the time to stand or sit down to examine the plant and decide what pruning is needed.

There are two main approaches to pruning: cut back the plant more or less evenly, and remove selected stems or branches entirely. These approaches can be combined. In this case of the lilac, cut below each faded blossom, just above a developing bud, and also remove entirely up to one third of the older branches to encourage new branches growing from the base.

Net week, we’ll consider seasonal pruning of evergreen shrubs.

Remember to sharpen your clippers to make your cuts clean and easy.

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