How to Save a Lilac Tree

Large and lush blooms are a spring and summer display of a healthy lilac plant.

The sight of a lilac struggling to flower or the plant's growth becoming too dense for light to reach the majority of its leaves can be distressing in any landscape. If left untreated, the plant might eventually die. Many lilacs begin to bloom with smaller and smaller flowers as a warning sign that it is overcrowded or in need of nutrients. Luckily, you can save a lilac tree by recognizing it is in trouble and taking action to remove excess branches and feed the lilac when the time is right.

Things You'll Need

• Rake
• Hand pruners
• Garden loppers
• String
• General purpose fertilizer
• Bark mulch

Instructions

1. Wait for your plant to finish blooming and the flowers to dry on the stem. Use a rake to pull away any debris from around the base of the tree including dead leaves, limbs and mulch. Lilacs consist of several branches or main stems all coming up from the ground, so work around the individual branches as best as possible to clear to ground level.

2. Check the tree for dead branches; they will have no leaves or dried flower heads on them. Trace each dead branch back to ground level and cut it horizontally as close to the ground as possible with hand pruners or garden loppers. Pull the dead branches out and discard.

3. Inspect the healthy branches that remain and select the strongest three to five branches that grow up from the ground to keep. Ideally, these branches will not rub against one another as they extend up from the ground. Tie a string around the base of each of these strong branches to mark them.

4. Cut away any living branches that aren't marked to ground level with a horizontal cut. Ease these branches out of the plant to avoid bending or breaking the strong branches you want to keep as the living branches are less likely to break when pulled out.

5. Cut off the marking strings when only the strong branches remain. Use hand pruners to clip off any remaining dried flowers from the tips of stems just behind the flower head. Deadheading the dried flowers like this should be done every year after blooming.

6. Feed the lilac tree with a granule or liquid feed according to the packaging directions for dosage amount and application method. Often feed for flowering shrubs is sufficient and bases dosage on the height of the plant.

7. Spread mulch around the entire base of the lilac tree to 3 inches deep and about 2 to 3 feet in diameter to keep weeds from competing for water. Water the tree with approximately an inch of water a week over the spring, summer and fall.

Tips & Warnings

• Feed your lilac twice every spring. Once as soon as you notice the buds swelling on the limbs and then again after the lilac has bloomed and the flowers are drying up.

References

• "Lilacs: the genus Syringa"; John L. Fiala; 2002
• "Reader's Digest Illustrated Guide to Gardening"; Carroll C. Calkins; 1993