Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Pruning
Like other paniculata hydrangeas, Limelight can be left unpruned indefinitely. However, if and when it does become necessary to prune, this is best done in late Summer, early Fall or Spring, at any time after it has finished blooming. Any pruning is merely done to limit size or for aesthetic shaping by removing stray, broken, dead or crossing branches. Paniculata hydrangeas are the only hydrangeas that can be pruned into a tree-form. To tree-form, simply remove lower branches by cutting them as close as possible to a trunk. If there are more trunks than you like, these can be removed as well by cutting them to the ground. Just be careful to notice how the removal of a trunk will effect the canopy.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Planting
Plant Limelight hydrangea in fertile, well-drained but moist soil. Consistently wet soils can cause problems with the roots. In the south it's best to plant Limelight in a site that provides morning sun with afternoon shade. The further north you go the more afternoon sun it can tolerate.

To plant, dig a hole no deeper than the root ball and two to three times the width of the root ball and fill it with water. If the hole drains within a few hours, you have good drainage. If the water is still standing 12 hours later, improve the drainage in your bed. Turn and break up the soil removed from the planting hole. When planting in compacted, dense or heavy clay mix in a good organic compost or a soil amendment at a 50/50 ratio with the soil removed from the planting hole. Remove your plant from its container and carefully but firmly loosen the root ball. Set the plant into the hole you've prepared, making sure the top of the root ball is slightly above or level the ground. Pull your backfill soil mixture around the root ball in the hole, tamping as you go to remove air pockets. Then water thoroughly and cover with a one to two-inch layer of mulch.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Feeding
I recommend feeding hydrangeas once or twice a year with a natural or organic plant food and/or mulch with organic compost. Many gardeners have success with just using the organic mulch. You can fertilizer in spring when new growth begins to emerge and again in late summer. Cease fertilization 2 months prior to the typical first frost date in your area. If you go with a chemical fertilizer I would suggest a well-balanced, slow-release shrub & tree type fertilizer. Do not fertilize plants with wilting foliage or that otherwise look diseased or stressed. Try to cure the problem first.

Gardenality.com · Gardenality Genius · Zone 8A · 10° to 15° F · Comment About Problems
I've seen no serious pest or disease problems with Limelight hydrangea. Consistently wet soil can cause root rot. In the South, as with most other hydrangeas, direct summer sun in the afternoon can cause the foliage to wilt.