June Plant of the Month | Hydrangeas
Considered the “Stars of the Summer Garden”, Hydrangeas shine from May through September. They are a group that has had incredible hybridizing work in the past 25 years to create new sizes, new colors and new forms to enhance our gardens.
Shop our hydrangea collection online or in store.
There are 5 types of hydrangeas that are hardy in Zone 5
- Annabelle (H. arborescens)
- Large leaf (H. macrophylla)
- Panicle flower types (H. paniculata)
- Oak Leaf (H. quercifolia)
- Climbing Hydrangea (H. petiolaris)
The Annabelle Hydrangea, a native species, is the group that has been the standard Hydrangea that would always grow in our gardens. Annabelle, a large white flower-head form was first discovered in 1910 and for many years it was the only Hydrangea that would grow successfully in the Zone 5 hardiness zone.
Large Leaf has colored flowers that change from pink to blue depending on the pH of the soil that they are growing in. Alkaline pH creates pink pigment and acidic pH creates blue pigment. This type is from Japan. They prefer part shade, preferably morning sun and afternoon shade. There are 2 types: mophead and lacecap.
The original cultivars, that were cold hardy to Zone 5, produced flowers on shoots that originated from previous seasons stems. If those woody stems were winter killed to the ground, the new stems that developed from the roots would not be able to produce flowers. In 1998, a true re-blooming type of Large Leaf was discovered in Minnesota. It was patented and trademarked as “Endless Summer” by Bailey Nurseries. It blooms on old wood and new wood all summer long. It changed the world for gardeners and hybridizers. Many cultivars have been developed and released from the “Endless Summer” start.
The Panicle flower types are from Japan and China. They have flowers that are cone-shaped (also known as panicles). They prefer sun, but will tolerate part shade. They flower later in the summer, starting in July and lasting through September. No Winter protection is needed for this variety. This group has had many new cultivars released in the past 10 years. They range in size from 10' tall by 8' wide to dwarf varieties that are 2-3' tall by 2-3' wide.
“Pinky Winky”
Oakleaf Hydrangea is another U.S. native shrub. The leaves are shaped like Oak leaves. It produces flowers on old wood. It blooms in late June into July. The flowers are conical shaped. It prefers shade, but will tolerate part shade. It has beautiful burgundy-red fall color. There are several cultivars ranging in size from 5-6' by 6-8' down to dwarfs that are 3' by 3'.
Climbing Hydrangea is a clinging vine originally from Asia. It can tolerate sun or shade conditions. The flowers are white and brighten a shady wall.
Pruning + Care Tips
Before picking up the pruning shears, you want to make sure that you know which ones you are pruning.
Annabelle types - They get cut back to 12-18 inches from the ground between the end of March and May 1st. They always get pruned every Spring. It is the ONLY one that has to be pruned every year. The others do not "need" to be pruned.
The Large leaf/macrophylla types - like "Endless Summer" only get pruned after the new growth has started in May. At that time you can see where the new buds are growing from the previous season's old wood. Sometimes there are dead parts of the branches from last season that need to be pruned off. You cut 1/4-1/2 inch above where the new shoots are growing out of the "old wood".
Paniculata types - It is not necessary to prune these at all because they initiate new grow just below the old blooms from last season which get "pushed off the ends of the branches" as the new growth develops. If the shrubs have grown larger than the space in which they were planted, it is possible to prune each branch back by 1/3 of the length. Do this before the new growth starts in May.
Climbing Hydrangeas can be pruned if the vines are growing in a direction that you do not want them to grow. Prune them also in May, but it is not necessary to prune them at all.
Shop our hydrangea collection online or in store.
Jennifer Brennan
Jennifer Brennan is the Horticulture Information Specialist, advising and coaching gardeners at Chalet for over 30 years