Caring for Hydrangeas
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Hydrangeas are one of the many old-fashioned shrubs that are enjoying new found popularity. Their bold foliage provides interest while the plant is not in bloom and the dried flower heads remain attractive through the winter months. Give this easy plant a try and enjoy it for many years to come!
The Flower Style
Mophead — The most well known flower style of hydrangea. This is a large, rounded cluster made up of hundreds of florets.
Lace-caps — They produce flat flower clusters with a ring of larger flowers surrounding the center of smaller florets.
Panicle — This type includes our native varieties: the quercifolias (oak leafs) and the paniculatas, which have large white, cone-shaped clusters. The flowers start out white, but many varieties fade to various shades of pink as they mature.
The Flower Color
Flower color (except the white varieties) is influenced by the pH of the soil. Many people buy this shrub for a particular flower color only to have it bloom a different color in successive years. If you have acidic soil your flower will tend to be blues. Neutral soils generally produce pale flower colors. Alkaline soils make pink or reddish tones. These colors can be encouraged or reversed within certain varieties. You have to begin treating the soil well before the blooms start to emerge from the tips of the plant for the color to be affected.
Water and Light
Keep your plants mulched and well watered. Hydrangeas LOVE water. Mulching helps to keep the roots cool and can supply nutrition as well. Plants benefit from a moist, fertile soil that does not dry out. Afternoon shade helps minimize wilting in hot locations and helps preserve and extend the length of the blooms.
Fertilizing and Feeding
Hydrangeas are heavy feeders, which means they benefit from additional nutrients. Slow-release or organic products are best because they deliver nutrients slowly, over an extended period of time. Extra nutrients should be applied early in the season when the plants are just leafing out. This makes food available when plants gain the most benefit from it. Do not fertilize in late summer; a fall application can be done when the leaves have dropped.
Pruning
Be cautious with your pruning. Leave old flowers through the winter, as they protect the new growth tips. Spring pruning should be delayed until you can distinguish between live and dead wood. At this time you can remove some (up to 1/3) of the oldest canes over 4 years old. If your plant is overgrown, do a major pruning immediately after blooming. This is done to reduce overall plant size and encourage more branching. If you wait too late in the season to prune, you will remove the tips which contain next year’s flower buds.
Disease and Pests
Hydrangeas are a long-lived plant. Fifty-year-old specimens are common. Hydrangeas are bothered by few pests and diseases, although spider mites can colonize a plant during extended dry periods causing a type of leaf damage that looks like leaf scorch or sunburn. These pests are easy to find on the underside of the leaves. Tap the leaves on a white sheet of paper and look for pinpoint sized crawling dots. Occasional mildew or leaf spotting occurs late in the season in humid climates. This is rarely more than a cosmetic problem. Ask for treatment strategies if necessary.