It is important to know when to prune your flowering shrubs, so you get the most flowers.   Timing your pruning is the key to success. 

Many early spring flowering plants already made their flowers all hidden and tucked away in the growth from last year.  Pruning at the wrong time will eliminate those flowers.  Here are some tips to keep you in the know.

Let’s take a Lilacs for example…

If you are out in the yard and your Lilac looks large and you have a pruner in your hand, it is late summer - and you just cut off the tips of the branches – your lilac will not bloom in the spring.  Let’s say you pruned them in fall, the same thing would happen in spring – no flowers.  Let’s say you prune your Lilacs in early spring before they leaf out - same scenario because you are removing the flowers that formed in the growth that developed last year. 

There are many different kinds of Lilacs, and the bloom times are common and hyacinthiflora types, then the French Hybrids, then the Miss Kim & Dwarf Korean types, the Canadian hybrids, and lastly…the Japanese tree Lilacs.  As each of these kinds of lilacs finish bloom – that is the perfect time to prune each of those lilacs without affecting next years flowers.  Older and overgrown Lilacs can be renewal pruned (removing the oldest stems out to the ground) and again right after bloom is done.

Let’s look at some of these other early spring blooming shrubs.

Flowering Quince is an early spring blooming rockstar.  Orange flowers bust out early and last for more than a month.  Then the plant breeders went to work and introduced many new varieties and new colors and some re-current blooming as well.  Trimming Quince varieties is best done immediately after the early spring blooms finish.  Then all of the new growth will make next years flower so no pruning after the initial prune is done right after the flowers are done.  Those newer varieties can and will throw some additional flowers throughout the summer but keep the pruning to that time following the early bloom always.

Forsythia varieties too have increased in number over the years.  Forsythia flowers are a welcoming sunny yellow or gold flowers arranged all along the stems in early spring before the leaves appear.

Forsythia varieties are typically fast growing and are all basically treated the same way for pruning.  As soon as the flowers are done (with their sometimes month-long show) in early spring – that is the time to prune!  Older and overgrown Forsythia plants can actually be cut down to the ground right after the blooms are done and all new growth will develop and still bloom the following spring.  Many of the newest selections remain much smaller and easier to incorporate into smaller landscapes.

Rhododendrons and Azaleas are treated the same when it comes to pruning.  Basically, Azaleas are considered Rhododendrons and are all included under the Rhododendron group.  Some are evergreen holding their leaves all year, and some do lose their leaves.  Reblooming varieties are being introduced all of the time but most of them are hardy in some of the warmer zones. 

Pruning Rhododendron and Azalea varieties is sometimes hard for many to want to do – why would anyone want to reduce the size of a plant that flowers on every tip?  Well, in some areas they can get big or need a little tweaking to keep them looking like you want them to.  Pruning Rhododendron and Azalea varieties can be done right after the first round of flowers begin to fade.  A hand pruner selectively reducing the length of any branches back into the body of the plant will allow the plant to continue in its more natural form.  Do not be afraid to prune these amazing plants.  They will respond beautifully to pruning and still form more flower buds in the new growth that happens after the pruning is complete. 

Magnolias are wildly showy and highly valued landscape plants.  Some Magnolias are grown as single stem trees, and many more are grown more like large shrubs with low branching or multiple stem plants.  Both methods of production are seen across the country, and preference is up to you.  Most Magnolias are larger growing plants and are used as a specimen plant or focal point in the landscape.

Pruning Magnolias may be necessary to correct the structure, tweak the form, or reduce the size a bit.  Pruning should only be done right after the amazing flowers finish.  (kind of a theme here).

Weigela plants have had extensive interest with breeders also.  New selections offer new form, smaller size, great and varied leaf color & flower colors, and reblooming capabilities stronger than ever.  Flowers in spring are best on last years stems so do not trim Weigela until that first round of flowers are done blasting off in June in many areas.  Waiting will allow your plants to bloom as heavily as Azaleas do, covering the stems with trumpet shaped flowers that the hummingbirds love. 

Older Weigela varieties were much larger and most likely need more pruning then the newer, smaller selections.  Larger, older selections can be renewal pruned by removing the oldest stems out to the ground leaving the thinner and smaller stems to take over.  If very overgrown you can wait until the first round of flowers finish and cut the branches all down to the ground and allow new shoots to take over and bloom on the tips in fall and the following spring too.

Birch and Maple trees can bleed sap if pruned early spring, so if you wait until they have leafed out, those cuts will not bleed and heal over quickly. 

Spring Flowering Bulbs are so very welcome in the landscape.  Keep your bulbs happy and healthy by pruning them the right way.  Enjoy the flowers.  When the flowers finish, remove only any seed heads that might form leaving all other green parts of the plants remain.  These green leaves and flower stems make food for the bulbs and will keep your flowers next year larger and healthy.  Many people like to cut off the leaves when the flowers are done but wait to cut any of the leaves off until they turn yellow and they have done their job of making more food for the bulbs. 

We hope this help you get the most flowers out of your shrubs!  If you have specific pruning questions, you can send them to [email protected], and we would be pleased to help you.