Q.Do Hydrangeas Grow In Semi Shade?
I am interested in a plant that can grow in 3-4 hours of sunlight and that keeps its color throughout the year. Do hydrangeas do this? And what type of hydrangea do you suggest? Thank you.
Hydrangea leaves typically require morning sun until 11am and then shade after wards. This requirement is strongly suggested during the hot summer months but in coastal areas, the sun exposure in the summer can dip into the afternoon hours as long as the soil is kept as evenly moist as you can and you maintain 3-4" of mulch past the drip line. Think: Cape Cod near you.
Hydrangea blooms do not keep their color during the growing season. They actually go through a series of color changes that last anywhere from several weeks/month and they all end in brown blooms.
In your zone 6b, Hydrangea arborescens, also known as Smooth Hydrangea is a good choice in planting locations with morning sun only while Hydrangea Paniculatas are a good choice for full sun planting locations. Both are extremely winter hardy to zone 3 and very bloom reliable in zone 6b. Choose any cultivar based parameters such as shrub dimensions (height/width), sun exposure, bloom type, bloom colors, time when they bloom, price, etc. Their blooms can initially be either green, white or a shade of pink. As these blooms age, they will change colors and the exact sequence will depend on the cultivar.
Hydrangea arborescens, also known as Smooth Hydrangeas, require morning sun and are somewhat compact for two feet to 6-7 feet. They produce mophead form blooms or lacecap form blooms.
Hydrangea paniculatas, also known as Pee Gee Hydrangeas or Panicle Hydrangeas can tolerate full sun in most areas of the US where summers are not harsh or hostile. They produce panicle-shaped blooms. The plants can be as short as 2 feet high and as tall as a small tree. They are sold as shrubs or in tree form.
Less bloom reliable, requiring morning sun only and winter hardy typically to zone 5 are: hydrangea macrophylla, also known as Big Leaf Hydrangea; French Hydrangea, etc., hydrangea serrata, also known as Mountain Hydrangea; and hydrangea quercifolia, also known as Oakleaf Hydrangea.
All three bloom on old wood but there are cultivars of the first two that are remontant and will produce a flush of blooms in spring and then a second flush in the summer. In zone 6b, I would recommend those remontant cultivars (they are labeled as rebloomers in ads) or Oakleaf Hydrangeas. Big Leaf and Mountain Hydrangeas produce mophead form blooms or lacecap form blooms. In planting locations with little direct sun, I suggest using cultivars from any series that get as high as 3 feet or less only in order to ensure bloom production in the late summer months.
Oakleaf hydrangeas are winter hardy to zone 5 and produce panicle-shaped blooms. Of all the types of hydrangeas, Hydrangea Quercifolia can be planted in areas with short sun exposures and it will not only bloom well but produce awesome fall foliage colors. It is also the most drought tolerant hydrangea but it should not be planted where the roots can remain wet for long periods of time as it can catch root rot easily.