Hydrangeas

Hydrangeas are easily grown, provide a long season of bloom, and make great companion plants. The flowers dry beautifully for arrangements, ranging in form from globose, lace-cap, or panicle shaped. Hydrangeas make good container plants and come in dwarf varieties, medium and large bushes, tree forms, and vines.

LOCATION: Site selection is important to obtain optimum flowering. Paniculata, arborescens, petiolaris and quercifolia species do well in full sun or part shade. The macrophylla group, Hortensia and Lacecap, prefer some shade from the hottest afternoon sun. The macrophylla group must be protected from frost pockets and strong winter winds to protect the flower buds.

WATER: Hydrangeas do not like to be dry. Amend moist, well drained soil with one-third organic material such as Superfines soil conditioner, pro-mix or composted cow manure. In times of drought, a thorough soaking will be necessary. Many hydrangeas, including macrophylla and arborescens, may droop in hot sun even if moisture is present. If leaves droop in the shade, water stress is likely. A good layer of mulch will supply nutrients, retain moisture and suppress weeds.

FERTILIZATION/COLOR CHANGE: A good, slow release fertilizer such as Merrifield Flowering Plant Food, Osmocote, or Hollytone fertilizer is recommended. Use aluminum sulfate to lower soil pH in order to produce blue flowers. Add lime to increase soil pH for pink flowers. Too much lime will make the soil too alkaline and may cause yellowing. Certain varieties do not change colors with the above additives, for example Annabelle will remain white.

PRUNING: Techniques vary with different types of hydrangeas. It may be better not to prune than to do so incorrectly.

Arborescens and paniculata produce their flowers on this years (new) wood; late spring frosts do not affect them. Leave them unpruned for a natural shape, cut to within 1 foot of the ground, train them into tree form, or remove all old wood to rejuvenate. Do this in early spring before new growth begins.

Hydrangea macrophylla (Hortensia and Lacecap), petiolaris, and quercifolia form flower buds and flower on the last years (old) wood. They require little, if any, pruning. Removing old flower heads is usually sufficient. In early April, after new growth appears and all danger of frost has passed, examine the canes and remove dead wood (scrape it with your fingernail, if you see no green, it is dead wood). Remove old flower heads to one inch above the first set of thick new buds.

Timing for drying hydrangeas is critical. Pick in late September to early October, when the blossoms are dry and feel crisp rather than soft. Cut macrophylla cultivars with very short stems. Arborescens may be cut with long stems. Remove all leaves and hang dry in small bunches in a warm, dry, area.