Hydrangeas

The 6 main groups of Hydrangea, each with their own characteristics, make for a varied plant group.

The popularity of these big, bold plants has grown over the few years.  Many people remember Hydrangeas from their childhood.  Today, we’re falling in love with them all over again.  Hydrangeas should be sited in moist, rich garden soil.  Hydrangeas can be categorized into 6 different types: mophead, lacecap, climbing, mountain, Oakleaf and panicle.  Each type has its own set of pruning rules and growing requirements

SIX TYPES:

Hydrangea anomala
Climbing Hydrangea

  • Best grown in partial shade
  • Well-drained soil is recommended
  • Late spring blooms on a clingy vine with dark green foliage
  • Requires a strong support structure
  • Clings and climbs attaching itself to many types of surfaces to help it climb
  • Somewhat slow growth rate
  • Grows up to 20’ tall

 

Hydrangea arborescens
Smooth Hydrangea

 

  • The biggest flowers in the Hydrangea family!
  • Plants may need staked or supported from weight of the flowers as the weight tends to bend the stems down to the ground.
  • Grow in morning sun and afternoon shade or dappled shade all day
  • Moist, well-drained soil is best.
  • One of the easiest types to grow
  • Bloom colors available are in shades of white or pink
  • Blooms every season, even after severe pruning or harsh, cold winters.
  • Favorite varieties: Annabelle, Bella Anna, Incrediball

Hydrangea macrophylla
Mophead Hydrangea

 

  • The most popular kind of Hydrangea grown in home gardens
  • Available in mophead types as well as lacecaps
  • Grow in an area protected from afternoon sun.
  • Keep soil moist and water well in dry weather
  • heading unlike older types.  This will allow for the production of new stems and blooms.
  • See below for information on changing flower color
  • Our favorites: Endless Summer, Let’s Dance Series, Bloomstruck

Hydrangea paniculata
Panicle Hydrangea

 

  • So easy to grow, prune and maintain!
  • Tolerates more sun and pruning practices than other types.
  • Will bloom each and every year on new wood.
  • Commonly also found in tree form (grafted onto a standard)
  • Favorites: Bobo, LImelight, Vanilla Strawberry, Quickfire

 

Hydrangea serrata
Mountain Hydrangea

 

  • Similar to the mophead Hydrangea (macrophylla) except it is smaller, more

    compact with smaller flowers and leaves.

  • Soil pH does not affect the flower colors

    of this species

  • Lacecap-type flowers
  • Favorites: Tuff Stuff Series, Twirligig

 

Hydrangea quercifolia
Oakleaf Hydrangea

 

  • Multiple season interest!  Large flowers in summer fade to a reddish-pink color plus oakleaf-like leaves are a nice shade of green that then turn to a pretty red in fall
  • Plant in sun or shade.  If planting in a sunnier spot, keep it well irrigated
  • Favorites: Pee Wee, Snow Queen, Gatsby Series

PLANTING

A partial shade site for macrophylla types is best.  Others will thrive in full sun.  Oakleaf Hydrangea varieties can take shade or sun.

Dig a hole 3 to 4 times the diameter of the root ball and 1 1/2 times as deep. Next, remove the container. Container-grown plants must have their outer root system broken and spread out or they will never become established. Simply cutting the roots with a knife in 3 to 4 places is not good enough, exposing about 1” of the root systems by vigorous shaking will work. Then, place plant in hole and backfill until the plant is at a level where grown in the nursery. Then, gradually backfill the hole while tamping soil around roots with your foot. Do not break the soil ball. Follow the watering directions then mulch with about 2” of bark mulch.

PRUNING

Each individual group has it’s own pruning practices.  Please see below.

Note: the NEWER Endless Summer Series of Hydrangeas will bloom on old, as well as new wood and almost never fails to bloom!

Pruning H. anomala

  • Prune after flowering in early summer
  • Trim extremely long shoots immediately after flowering
  • Will tolerate a hard pruning in spring is likely to reduce flowering for the next few months

Pruning H. arborescens

  • This type will bloom more prolifically when pruned annually
  • Cut back last season’s stems to a pair of healthy buds in spring
  • To produce larger flowers, hard prune in spring to the lowest pair of healthy buds (usually at 2 feet tall), creating a low framework of branches

Pruning H. macrophylla

  • Older mopheads such as ‘Nikko Blue’ or ‘Pink Beauty’ should only have the dead wood removed the next season, in early spring.  These stems appear hollow and show no buds.  Trimming of these varieties is not necessary or recommended.
  • Newer mophead types are bred to bloom on both old wood and new wood to make trimming a breeze.  Cut out any dead stems in early spring before leaves sprout.  Newer varieties also take well to dead-heading unlike older types. This will allow for the production of new stems and blooms

Pruning H. paniculata

  • Prune in fall, winter or early spring to shape

Pruning H. serrata

  • Normally do not require any pruning. If you do need to prune, follow the same rules as for the macrophylla group.  Prune just as the flower fade.

Pruning H. quercifolia

  • Pruning is typically not needed on these dwarf plants, but it may be pruned to shape immediately after the spring bloom.

BLOOM COLOR

The most interesting feature of showy hydrangea flower heads is their ability to change color according to the pH level of the soil. Hydrangeas have blue flowers where the soil is naturally acidic, and pink or red blooms in alkaline soil. This gives the home gardener a certain amount of control over the color scheme of the hydrangea bed. Winter is a good time to start planning these changes – by the time the hydrangeas are in flower it’s too late.

To change the color of Common Hydrangeas, add 5 to 8 Tbs. of aluminum sulfate for blue or 12 to 15 Tbs. of dolomitic limestone (pulverized lime) for pink per 10 square feet. Pull back the mulch and lightly mix into the top layer of soil and water thoroughly. It may take 2 years for a complete color change.

WATERING

Water at initial installation.  Use as much water as necessary to thoroughly soak plants and wet entire bed.  Then, water the plant every 3 days for 3 weeks.  After the 3 week period, water only when necessary. Check soil moisture around plant before watering.  Remember, Hydrangeas are high water users, and, during hot periods, should be kept well watered.  If temperatures are above 85°F, more frequent waterings may be needed.

FERTILIZING

Fertilize approximately on April 1st, May 20th, July 4th, August 15th and October 30th. Use an acidic fertilizer such as Holly Tone. If using a liquid fertilizer, do not apply it to the blooms of the plant.

FAQs

Question: Why isn’t my Hydrangea blooming?
The main answer is wrong pruning technique and timing.  Be sure to review group pruning instructions before pruning.  See video below.

Question: My Hydrangea leaves have brown crispy edges, what did I do wrong?

Your plants are probably too dry.  It would be best to keep them on a regular irrigation schedule.

Question: How much sun do Hydrangeas need?

Most Hydrangea types prefer morning sun only but most Paniculata types can tolerate full sun.

Question: Why is my Hydrangea wilting?

Wilting is a common occurrence, especially on macrophylla types, when the soil is too dry. Hot mid-day sun causes excess transpiration of water through the large leaves.

Question: Are there any insects or disease I should worry about?

No, do not worry.  Hydrangeas can sometimes get a case of powdery mildew or leaf spot but it is not common and usually will not harm the overall health of the plant.