Extension Master GardenerSM Volunteers of Buncombe County

hydrangeas

Online Seminar: Heavenly Hydrangeas June 16

Gardening in the Mountains presents
Heavenly Hydrangeas

Thursday, June 16 2022
10 to 11 a.m.

Virtual attendance via Zoom video and audio internet connection

Presenter: Irene Palmer, NC State Mountain Crop Improvement Lab

Dive into the varied forms and attributes of the popular and diverse world of Hydrangeas. Irene Palmer, with the NC State Mountain Crop Improvement Lab in Mills River, NC, will take us on a journey to explore how selective breeding has transformed these charismatic garden champions. Learn about garden standards, new varieties and the best care and maintenance you can provide to help them thrive. 

Registration: The talk is free but registration is required. Please click on the link below to
register. If you encounter problems registering or if you have questions, call 828-255-5522.

Zoom seminar access: After registration, you will receive an email with instructions and a link to join this online live broadcast via Zoom. The ability to access Zoom through a computer, tablet or smartphone with a reliable internet connection is necessary to attend. 

Time to Maintain: How to Prune Hydrangeas

Walking amidst “Munchkin,” “Ruby Slippers,” and “Snow Queen” at a local plant nursery, I wondered if I had wandered into some magical land “over the rainbow.” I was in the section of the nursery dedicated to hydrangeas!

Hydrangeas_Shinji W_CC BY 2.0_Flickr
Hydrangeas – a rainbow of color

Hydrangeas include more than 75 species of evergreen or deciduous shrubs native from Asia to North America. They are widely grown, relatively pest free, and require minimal annual maintenance. Consider including them in your landscape design—they will bring you multi-season enjoyment. 

Hydrangeas in North Carolina
The most common species of hydrangeas found in North Carolina landscapes are:

  • Bigleaf hydrangeas (Hydrangea macrophylla) come in two flower types: lacecap and mophead. If you adjust soil pH, you can modify their bloom color. They will bloom blue in acid (below 6) pH soil and pink in high (above 7) pH soil. This is a function of aluminum availability. White bigleaf hydrangeas will not change color with soil pH. There are over 1,000 cultivars of this species—some recent introductions may re-bloom on new wood. In Western North Carolina most bloom from June to August.
  • Mountain hydrangeas (Hydrangea serrata) also come in both lacecap and mophead flower types. They grow 2 to 5 feet high and 4 to 6 feet wide. There are over 100 cultivars. They are native to Asia, not our mountains, and bloom in May.
  • Oakleaf hydrangeas (Hydrangea quercifolia) grow 4 to 8 feet high and wide and are one of the hydrangeas native to the southeastern states. They flower in June with blooms lasting three to four weeks. Leave the spent bloom heads on the plants to add winter interest to the garden.
  • Smooth hydrangeas (Hydrangea arborescens) are native to our area and grow 3 to 5 feet high and wide. Flowers appear in June and last 3 to 4 weeks.
  • Peegee hydrangeas (Hydrangea paniculata) grow 15 to 25 feet high and 10 to 20 feet wide, if left unpruned. Their flowers open white from June through August.
  • Climbing hydrangeas (Hydrangea anomala subsp. petiolaris) are vines that can grow 60 to 80 feet tall if left untrimmed. Asian natives, they are slow to establish, but you will enjoy their ability to climb just about any vertical surface. Bloom time is late June to early July.

 Pruning care

  • Hydrangea macrophylla, H. serrata, and H. quercifolia bloom on old (last year’s) wood—prune after flowering. You can trim to shape them to fit into your landscape design. Remove dead, diseased, and damaged limbs at any time.
  • Hydrangea arborescens and H. paniculata bloom on new wood—prune in late winter (February to early March). They benefit from being cut back to six inches off the ground (i.e., rejuvenation pruning). Promptly remove all old, dead, diseased, and damaged stems.
  • Hydrangea anomala subsp. petiolaris requires very little pruning—train to grow this climbing hydrangea on its support surface. 

Article written by Bob Wardwell, Extension Master GardenerSM Volunteer.

Learn more
It’s All in the Soil! The Chemistry Behind Hydrangea Colors
YouTube video from the American Scientist

Prune hydrangeas at the wrong time and you snip off the season’s blooms.
by Glenn Palmer, Buncombe County Extension Master GardenerSM Volunteer

Smooth and Oakleaf Hydrangeas
by Ervin Evans and Richard E. Bir
Horticultural Science, NC State Extension

Prune hydrangeas at the wrong time and you snip off the season’s blooms.

Late winter is pruning time for many trees and shrubs, but the majority of questions we receive relate to hydrangeas. When to prune depends on the type of hydrangea you have. Here are some guidelines:

Bigleaf and lacecap hydrangeas; Hydrangea macrophylla: This common hydrangea usually has pink or blue flowers, the blue shades a result of more acid soils. For a mature plant, remove the dead wood in late winter by cutting those stems to the ground. This will allow access to more air and light. Any other pruning should be completed after the flowers fade—not earlier than July; no later than the first week in August. Later pruning will destroy flower buds developing into the next blossoms.

hydrangea_macrophylla
Hydrangea macrophylla or Bigleaf hydrangea

Smooth hydrangea; Hydrangea arborescens ‘Annabelle’: Because of its untidy growth pattern most gardeners annually prune the entire plant to 6-12” from the ground. This should be done in late winter as the flowers appear on the current year’s growth.

Hydrangea arborescens
Hydrangea arborescens or Smooth hydrangea

Peegee hydrangea; Hydrangea paniculata grandiflora: Develops into a large shrub producing many smaller blooms. In early March, severe pruning, cutting back to only two buds at the base of each stem, will produce a smaller shrub with larger flowers on current year’s growth.

Hydrangea-paniculata-Limelight
Hydrangea paniculata ‘Limelight’ or Peegee hydrangea

Oakleaf hydrangea; Hydrangea quercifolia: Native and generally left to grow its natural form. Blooms for a long period on last year’s growth. Any pruning should be done as soon as the flowers begin to fade.

Hydrangea-quercifolia-Snowflake
Hydrangea quercifolia ‘Snowflake’ or Oakleaf hydrangea

For most woody plants, follow this rule: “If the plant blooms early in the season on last year’s growth, prune after it blooms—not now!” (Forsythia, for example.)

If the plant blooms later on growth that occurs this year, do only limited cutting now. Wait until after the blooms have faded before major pruning.

Article written by Glenn Palmer, Extension Master Gardener Volunteer.

Contact Us

Buncombe County Extension Office
49 Mount Carmel Road
Asheville, NC 28806
Helpline 828-255-5522

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