Correct pruning in the spring is one of the most important factors in obtaining exciting results from your garden plants. As getting it right is largely about timing, it’s important to be on the ball at this time of year with your secateurs, loppers and cutters. Spring being the onset of the growing season, and in dry Mediterranean climates, the primary growing season, is the ideal time for pruning most, but not all plants.

Other than with trees, which are a separate category, the purpose of pruning is to induce more and superior flowering, denser and more compact growth, or both together. Cutting back herbaceous perennials for instance, prevents the plants from becoming bald and leggy, while pruning shrubs maintains bushy, green growth from the top to the ground.

What not to Prune

Remember that deciduous trees and shrubs should never be pruned in the spring, because of the sap rising in the branches at this time. Deciduous plants, i.e. broadleaved plants that originate from cold winter climates, should be pruned during their dormancy in the winter, although light pruning is possible in the summer.

It is also important to know that flowering shrubs whose blooms develop from buds that originated in the previous spring will not flower if pruned now. Lilacs and some species roses are typical examples, and the complaint– “my rose bush never seems to flower” – is a common refrain.

Similarly, fruit trees that belong to this category will never produce fruit if the flower buds are accidentally removed by early pruning. As a rule therefore, delay pruning trees and shrubs that flower on the previous year’s growth, until the end of the flowering, while being careful not to remove the spent flowers of fruit trees. 
 
Pruning Perennials

A common mistake with perennial bedding plants is to wait until the last of the flowers have withered before deadheading and pruning back the plants. Many species in use in hot, dry climate gardens fall into a semi dormant state in the summer, while flowering is their final burst of activity towards the end of spring.

It is far better to give up on the last 25% or so of flowers and cut the plants back in order to induce vegetative growth and thus cause the plant to “cover itself” in foliage before the onset of summer. This applies particularly to Ice Plants, African Daisies, and many herbs of Mediterranean origin, such as Sage, Artemisia, Lavender, and Thyme.

Pruning Shrubs and Bushes

Without pruning, most shrubs ape their larger cousins, and develop a tree-like habit in growth and form. Sometimes, a bush grown as a small tree can be a valuable and creative addition to the garden. But in general, the role of shrubs is to create a screen or background of dense, compact foliage. To wait until the middle of the summer, is to cause the plant to waist the valuable energy it has expended by its spring growth.

While tree pruning involves the careful and judicious removal of a small number of limbs, shrubs can be shortened by about a half of their height, while old wood can be removed altogether. This applies to flowering shrubs like Hibiscus, Trumpet Vines, or Cestrum, as to purely landscaping bushes.