Pruning old wood versus new wood?

When do I prune?  What is old wood versus new wood?

In my description of many flowering shrubs and trees, I refer to the correct time to prune as to whether the blooms come from old wood or new wood.  Knowing the correct time to prune is is important so you don’t interrupt the plants bloom cycle. Knowing if your plants bloom on old wood or new wood will determine the best time to prune in order to promote healthy growth and “flower power”. This often depends upon the bloom time and the species.

What do you mean by Old Wood?

Those that bloom on old wood usually bloom in the spring ( like lilac and forsythia).  Their blooms are formed during the summer and fall in preparation for spring.  The growth on last year’s stems or branches is known as old wood.  These plants are usually pruned right after they finish blooming.  This stimulates growth and greater flowering the next year.  Prune after flowers have faded to thin and shape as desired.  Since the blooms form on old wood, you need to keep in mind that more wood you remove will result in less blooms next Spring.

Prune after blooming     (Blooms on Old Wood)

Flowering Almond            Beautybush

Purple Sand Cherry         Chokeberry

Cotoneaster                      Deutzia

Hydrangea, Bigleaf ***   Hydrangea, Oakleaf

Lilac                                 Mockorange

Quince, flowering         Spirea, Spring flowering

Viburnum                          Weigela

What do you mean by New Wood?

Bushes and trees that bloom on new wood are usually summer bloomers and bloom on stems that develop during the current season (like ButterflyBushes and Rose of Sharon).  These can be left alone until the following spring.  That spurt of growth that appears in spring will be the branches to produce that years blooms.  Trim the new wood bloomers in late winter or early spring to encourage new growth and blooms.  Prune these during their dormant season (before new growth has started).  They can handle severe pruning if necessary to shape and trim.  Remove any damaged limbs or those that cross.

Prune late Winter to early Spring (Blooms on New Wood)

Barberry, Japanese           Butterfly Bush

Red Twig Dogwood           Burning Bush

Wintercreeper                   Forsythia

Fothergilla                         Fringetree

Hydrangea, panicled      Crape Myrtle

Kerria, Japanese               Rose of Sharon

Snow berry                        Winterberry

Spirea, Sumer flowering

 

*** There are new cultivars of Hydrangea that bloom on both old and new wood.