Sunday, June 19, 2016

Are Your Lilacs Blossoms Looking “Rusty’? Time to Prune By Joyce D’Agostino

Photo Joyce D'Agostino
For those who love lilacs, having those wonderful blooms and fragrance is a welcome end of the long winter. Lilacs now come in various shades of purple, lavender, pink and white. 
But now that the season for lilac blooming is over, you may notice that those lovely flower heads are replaced with unsightly rusty colored heads. This is normal for your lilac and not an indication of a decline in the shrub or a disease. However now that the blooms are done and before the lilac prepares for next season, you have a window of time now in June to do some removal of those old flowers as well as some pruning.  
Many lilacs can grow to be large sized bushes, and keeping them maintained helps preserve their beauty and health. It is recommended that this pruning be done before early July because after that time, the plant begins to prepare for the next season’s growth and removal of the buds may cause a loss of some of the flowering for next year. So planning for your pruning to be done before possibly the July 4th holiday may be a good target date.

Lilacs also can have a tendency for developing Powdery Mildew. You will notice that this has developed by the white coating on the leaves. Powdery Mildew can often develop when the plant has poor air circulation, so pruning is another important step in the health of your lilac. Information about this fungal infection is found below.
Continue to watch you lilac during the summer for any storm damage. If limbs are broken or split due to wind or hail damage, removing them as soon as possible even if they have set new growth helps prevent insects from entering the stems and branches through the split wood. 
For some great tips and information about pruning your flowering shrubs like lilacs, refer to these garden bulletins from CSU: