Growing and Pruning Hydrangeas

September E-News from Viette's Volume 11: No. 9
Lori Jones, Editor September/2015

A monarch butterfly collects nectar

from a Vitex flower spike.

September is a beautiful time to be
in the garden!

If you think that September means the end of the "flower show" ...

Think again!

Visit Viette's this September!

Our gardens are full of beautiful September color; from the bright blooms of Helianthus, Japanese anemones, and Buddleia to the colorful butterflies that swarm all over them.

Our gardens are ALWAYS OPEN for you to enjoy!

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Through September

Plant of the Month

Hydrangea paniculata

Hydrangea

Beautiful shrubs for the Garden!!

Old-fashioned Grandeur
Hydrangeas have been garden favorites for many years and understandably so! The diversity found in this family of flowering shrubs is impressive. They are usually grown for their large clusters of showy summer flowers but their value in the landscape goes well beyond their beautiful blooms!

The Five Types
There are five different types of hydrangea and each has it's own unique characteristics. Most thrive in full sun or part shade and they prefer moist, well-drained soil that is rich in organic matter to perform their best. For pruning purposes, it is VERY important that you know which type(s) you have in your garden - so SAVE the LABELS!
See our 'Tip of the Month' for pruning methods.

Hydrangea arborescens -
A wonderful species that includes the popular cultivar 'Annabelle' which produces huge white flowers up to 10" across. These hardy hydrangeas bloom from June - August and grow 3'-5' tall. This species prefers partial shade. The flowers are excellent for drying and using in fall arrangements. Zones 4-9.

Watch Mark's video tips on growing 'Annabelle' and drying hydrangea flowers.

Hydrangea 'Annabelle' at Viette's

Hydrangea paniculata - This tall variety grows as a large, upright, spreading shrub or it can be developed into tree form through pruning. It produces large conical flower clusters from July to September and grows 10' - 25' tall. One of the most cold hardy types of hydrangea. Zones 3-8.

Watch Mark's video tip on how to train Hydrangea 'Tardiva' to tree form.

Hydrangea paniculata 'Tardiva'

Hydrangea macrophylla -
These are commonly grown hydrangeas that produce large blooms on wood produced the previous year. This species includes the mophead hydrangeas with their huge round flower heads and the lacecap hydrangeas which bear round, flat clusters of tiny fertile flowers surrounded by a ring of showy open petals. The bloom color may be pink or blue depending on the pH of the soil they are grown in (blue in acidic soil, pink in basic or alkaline soil).

Lacecap hydrangea

The flowers of Hydrangea macrophylla are excellent for drying. This species is less hardy than the other species and in colder regions of Zone 6, they may grow well but not be "bloom hardy" meaning that the plant survives but never or rarely flowers because the flower buds are damaged during the winter. Protect the stems in winter by packing them with straw, tying them together, and wrapping them with burlap.

Reblooming Types

Recently, several hardy reblooming cultivars have been developed from Hydrangea macrophylla. These include the Endless Summer Collection. These shrubs bloom on both new and old wood and are hardy to Zone 4.

Hydrangea 'Endless Summer' is a reblooming form of H. macrophylla

Hydrangea quercifolia - Named for its deeply lobed oak-shaped leaves, Oakleaf hydrangea is noted for its brilliant deep reddish fall color. Large erect clusters of white flowers grace the shrub in summer with peak bloom in July. This species grows 4' - 8' tall and is hardy in Zones 5-9.

Oakleaf hydrangea
Karan A. Rawlins, University of Georgia, Bugwood.org

Hydrangea anomala ssp. petiolaris - This is a hardy climbing hydrangea which can reach up to 80' tall if left unpruned. The strong vines have attractive cinnamon brown bark and beautiful clusters of white flowers from June - July. They grow well on brick or stone walls, or on arbors and trellises. Zones 4-7.

Bottom Line
These are amazing shrubs and every gardener should find a place for at least one or two in the garden!

Come visit Viette's and see how magnificent these can be as mature specimens in the garden!

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Tip of the Month

Hydrangea paniculata 'Tardiva' in tree form

Hydrangea paniculata 'Tardiva'
pruned to tree form

Pruning Hydrangeas!

We always get a lot of questions on the radio, on our discussion board, and in our garden center about when is the correct time to prune hydrangeas. This is a great question because when and how you prune your hydrangeas can mean the difference between having multitudes of glorious blooms or . . . no blooms at all!

The trick is knowing which of the five different types of hydrangea you have. So, when you plant, be sure to save the label! That way, when it is time to prune, you can do it correctly without sacrificing the beautiful blooms. Keep in mind that certain types of H. macrophylla may never bloom for you if they are not bloom hardy in your area .

Tips for Pruning Hydrangeas

Even though there are five different types of hydrangea, each of these falls into one of two pruning groups, based mostly on whether they bloom on wood produced in the current year (new wood) or wood produced in the previous year (old wood).

Pruning Group 1

This group includes the species that bloom on old wood - Hydrangea macrophylla (aka. mophead, lacecap, bigleaf, hortensia, or florist hydrangea) and Hydrangea quercifolia (oakleaf hydrangea).

Lacecap hydrangea

Flower buds of these hydrangea are formed in August through October depending on the species.
These hydrangea do not necessarily require annual pruning.
Prune these, if needed, right as the flowers begin to fade usually in mid-summer.
To be safe, DO NOT prune them after July.
For mature established shrubs, the regular removal of 20% of the oldest stems (cut at soil level) will keep the plant vigorous and blooming well with larger flowers. Do this in the spring.
Deadheading or removing the spent blooms can be done continuously through the season.
Some evidence indicates that leaving old blooms on the plant through the winter may help protect the tender buds below them. In colder areas, consider leaving them and removing them in the spring after the shrub breaks dormancy.
Dead and damaged stems should be removed whenever they are noticed.
Oakleaf hydrangea does not require annual pruning and should be pruned mainly to remove dead or damaged stems or to limit its height.
Watch Mark's video tip on "Why Hydrangeas Don't Flower"

Pruning Group 2

This group includes the species that bloom on new wood - Hydrangea arborescens (smooth hydrangea), Hydrangea paniculata (Panicle or PeeGee Hydrangea), Hydrangea anomala ssp. petiolaris (Climbing Hydrangea), and reblooming varieties of H. macrophylla such as the 'Endless Summer' Series.

Hydrangea arborescens 'Annabelle'

These species of hydrangea produce flower buds on the current season's growth about one or two months before they bloom.
In general, these can be pruned after they finish blooming up until they begin producing flower buds in the spring; i.e., fall, winter, or early spring.
H. paniculata does not require annual pruning except to remove wayward branches and stems. This species can be developed into a single or multi-stemmed tree by maintaining just the desired number of stems/trunks and pruning out all but the upper branches. It can also be cut back to 18" - 24" from the ground to rejuvenate it or to limit its size.
H. arborescens cultivars such as 'Annabelle' can be pruned to the ground in the fall or late winter before active growth begins in spring. This promotes large flowers! If your Annabelle hydrangea tends to flop over from the weight of the flowers, try pruning to 18" - 24" rather than cutting them to the ground. This will allow the stems to thicken and provide stronger support for the large blooms. Watch Mark's video tip on pruning Hydrangea 'Annabelle'.

Reblooming types such as 'Endless Summer' can be deadheaded throughout the season to encourage continuous bloom.

Climbing hydrangea

Climbing hydrangea requires little pruning except to limit its growth to the space you have. Early spring or in summer after flowering is the best time to prune this species.
Dead or damaged stems should always be removed whenever they are noticed.

August Lectures at Viette's

Join us at the farm for these informative lectures ...

Saturday, September 19 at 1:30 pm

Gardening in the Fall

If you think that just because it's September, the "flower show" is over, think again! You won't believe how many plants are still looking great and how much color there still is in the garden. Plan for fall color through foliage, flowers, and berries. Use ornamental grasses and hardy mums to give a real feeling of fall. Andre will introduce you to some other wonderful fall blooming perennials and add a little color to your life this fall! Free lecture

Saturday, September 26 at 1:30 pm

Techniques of Plant Propagation

Tall bearded iris clumps can be rejuvenated by dividing.

A wonderful fall hands-on workshop! Plant propagation is an exciting, self-satisfying, and money saving activity! Learn how to landscape your property using your own plants. Mark will teach you the best methods for many different plants including techniques of dividing, taking cuttings, layering, and seeding. Take home loads of plant divisions! A propagating demonstration tour is included.

Please pre-register by calling 800-575-5538;
$30 fee, two for $50

From the Viette's Views Blog ...

Don't Blame the Goldenrod!

08-27-2015 08:26:31 AM

It's late summer and your eyes have become itchy and watery. Your nose is running and stuffy because you've been sneezing like crazy. There must be some pollen in the air wreaking havoc with your respiratory system! You look around and see many bright yellow goldenrods in the fields and along the roadside so naturally [...] ...»

Speaking of Goldenrod ...

From the Viette's Views Archives

The GALL of those Gnats!

09-07-2011

As summer comes to a close and the beautiful fall season is upon us, I am enjoying the last blooms of our daylilies, Coreopsis, hardy hibiscus, and summer phlox. But fall doesn't spell the end of color in the perennial garden. I am eagerly looking forward to the late blooms of Helianthus, goldenrods, chrysanthemums, sedums, and Japanese anemones. Read more ...

A Few Tips for September

Now that the hot summer days are almost over, it's time to enjoy the garden again.

Extend Your Gardening Season

Hellianthus salicifolius produces masses of vibrant yellow blooms.

Helianthus salicifolius produces masses of vibrant yellow blooms.

Go out and take a look at your garden - are the blooms fading away? Is the cheerful color of summer disappearing? Maybe your garden needs a face lift!

Now's the time to add some fall dazzle!

September is one of the best times to plant trees, shrubs, and of course, perennials!

Fall Blooms

For your sunny area, the golden petals and deep brown centers of Helianthus and the Rudbeckia varieties give you rich, earthy color through the month of October.

Colorful Echinacea varieties

Add some of the Echinacea cultivars for large, vibrant splashes of purple-red, orange, yellow, and white. Then there are the many varieties of our old favorites, the Asters, in their vivid purples, pinks, and blues; the Sedums, with their large, handsome blooms and interesting succulent foliage; the beautiful blue-gray, aromatic foliage of Perovskia with its graceful spikes of silvery-blue flowers; and the beautiful cobalt blue blooms and contrasting red fall foliage of Ceratostigma (Plumbago).

Add a Garden Showpiece

Crape myrtles come in all sizes and bloom colors.

If you need a large "centerpiece" for your fall garden, consider the spectacular hardy Hibiscuswith its huge, colorful flowers or the long-blooming butterfly bush, Buddleia davidii, with beautiful flowers in many shades of purple, pink, and white that will continue to attract flocks of beautiful butterflies until frost. An excellent specimen tree or shrub for the fall garden is crape myrtle, Lagerstroemia indica. This exceptional deciduous ornamental has a long blooming season of showy flowers, a stunning fall season of blooms and colorful foliage, and a winter season of dramatic architectural beauty highlighted by distinctive cinnamon-colored exfoliating bark. What more could you ask for? Anemone September Charm

Fall Color for the Shade

For the shade garden, you must try Anemone japonica and hardy begonia, Begonia grandis! What wonderful late blooming perennials to compliment your Hosta, Astilbe, and other shade loving favorites.

Color From Foliage

Sourwood tree dons brilliant
red autumn foliage.

Don't forget the perennials which have such colorful foliage that they know no one season. Enhance the border garden with the beautiful red foliage of some of the new Heuchera varieties or the striking peach colored foliage of Heuchera 'Caramel'. The silvery Artemisia adds a softness to the stronger colors of Asters, Echinacea, and other perennials. The beautiful dwarf shrub, Spiraea 'Gold Flame', turns from fiery gold in spring to a dazzling red, copper, and orange in the fall. Sourwood, Oxydendrum arboreum, turns a brilliant scarlet in the fall. It is a lovely understory tree to add to your landscape.
So many others ... Visit the gardens at Viette's or a public garden or arboretum near you to get more great ideas!

Don't miss Andre's talk, "The Garden in Fall" on Saturday, September 19th at 1:30 PM

Dividing and Transplanting ...

Not only is September a great time for planting, it is also a great time to divide many perennials because the warm soil, increased likelihood of rain, and fewer insect and disease related problems combine to make perfect growing conditions for your new divisions. New roots will grow all winter and, come spring, will be strong enough to support lush new top growth. These divisions, supplemented with new perennials, can be used to create a new bed or to extend an existing garden.

When transplanting and/or dividing perennials that are already planted in the garden, you will want to cut the foliage back so the plant's energy can be directed to the roots instead of to the foliage and flowers. It will also reduce water loss through the leaves.

Always water deeply every 7-10 days after transplanting until the new plants have become established. Apply a 2"-3" cover of mulch after planting (except for peonies and tall bearded iris).

In general, fall blooming perennials like Chrysanthemums, Japanese anemones, ornamental grasses, and asters should be divided in the early spring before they begin growth.