Lesser-known Hydrangea, a Garden Star

On the evening before Mothers’ Day, I was forced to pick up a few items at the big blue retail store. Yep. Saturday night at Wally World. Lucky me. As I sat in my car, summoning up my strength for the task ahead, I witnessed blue and pink orbs floating from the store’s doorway. They disappeared into cars in the parking lot. When I donned my eyeglasses (don’t fret - I wore them while I was driving), those blue and pink orbs materialized into giant Hydrangea flower heads atop plants that were on their way to be a Mothers’ Day present the next day, no doubt. Wonder how many of those will survive to bloom again next year?

There is much more to the genus Hydrangea than those big pink or blue mopheads, Hydrangea macrophylla. A lesser known but marvelous species is the native Hydrangea arborescens. The common name for this beauty, Smooth Hydrangea, has been displaced by Mountain Hydrangea in a nod to its origins. In the wild, H. arborescens is a lacecap, but in the 1960s, a mophead type was discovered growing in Illinois. It was subsequently introduced to the market as ‘Annabelle.’

‘Annabelle’ remains immensely popular. It is hardy in zone 4 to 9, withstands more sun and needs less water than the large-leaf mophead varieties, and has huge (up to 12 inches across) white flowers from summer through fall. The only downside is weak stems that do not support the giant flowers, especially when rain increases the weight of the already-heavy flowers. Sadly,  puny stems allow the beautiful flowers to droop into mud.

‘Incrediball’ was introduced in 2009 as an improved ‘Annabelle,’ with mature size of 5 ft tall and 5 ft wide. It shared all the same positive qualities as its predecessor but with much stronger stems and even larger flower heads – up to basketball-size! Soon, non-white cultivars followed as introductions from Dr. Thomas Ranney of NC State University and Spring Meadow Nursery. Here are a few newer choices:

·‘Incrediball™ Blush’ has soft pink flowers; 5 ft tall x 5 ft wide. ·‘Invincibelle™ Ruby’ has deep red flowers; 4 ft tall x 4 ft wide. ·‘Invincibelle™ Spirit’ has pink flowers; 4 ft tall x 4 ft wide. ·‘Invincibelle™ Spirit II’ has pink flowers that age to a gorgeous green; 4 ft tall x 4 ft wide.
·‘Invincibelle Mini Mauvette®’ has mauve/purple flowers; 3 ft tall x 3 ft wide.
·‘Invincibelle Wee White® has white blooms; 2½ ft tall x 2½ ft wide.
·‘Invincibelle Limetta® has greenish flowers; 4 ft tall x 4 ft wide.
·‘Invincibelle Garnetta® has ruby flowers; 2½ ft tall x 2½ ft wide. (Proven Winners website describes the color as ruby-red, not garnet. Weird, huh?)

Site H. arborescens in half sun to mostly sun. Shrubs in more sun will require more irrigation than their sisters planted in shadier locations. All bloom on new wood, so they are resistent to bud death due to late freezes. Prune hard in late winter, cutting stems back to 6-12 inches just before new growth starts. Dried blooms can be removed at any time and used in flower arrangements. The dried flowers can be spray painted to match any décor – I’m partial to deep burgundy or silver, for use around the holidays.

Unlike Hydrangea macrophylla, Hydrangea arborescens do not change colors when soil is altered. White flowers stay white. Pink flowers stay pink. Fertilize once in spring, and provide sufficient irrigation to prevent plant wilt without creating a boggy soil. Plants prefer neutral to acidic soil. If in doubt, check the grow zones for your preferred cultivar. Most are hardy in zones 4-9.

Incrediball™ flower

Invincibelle Spirit™ flower

Amsonia - A Two-Season Star

Amsonia hubrichtii, (pronounced am-SO-nee-yuh hew-BRIK-tee-eye) is flowering right now. This Arkansas native’s soft blue flowers are held at the top of tall stems that waft gracefully on the breeze. Leaves are narrow, leading to the common name Threadleaf Blue Star. Its fine, feather-like texture contrasts well with broad-leaf perennials like Black-Eyes Susans or Coneflowers. It also looks pretty when planted next to burgundy foliage plants like Ninebark, Smokebush, or Loropetalum.

While the spring flowers are pretty, Amsonia’s best season is fall. Those narrow leaves turn a golden yellow that glows in sunlight. For maximum impact, pick a site where the late afternoon sun provides a backlight.

Amsonia is undemanding. Give it full sun or mostly sun and it will be happy in zones 5-8 . Too much shade or excess water will cause it to flop. In rich soil, it may grow so tall that it opens up in the center in late summer. It takes at least a year or two for Amsonia to reach its potential. Don’t pull it up prematurely. Mature plants will reach heights of three feet, with a equal spread. Prevent the flopping or center separation by pruning it back to a height of six inches immediately after flowering ends. Cut to ground level just before spring growth commences.

Amsonia hubrichtii was the Perennial Plant Association’s “Plant of the Year” in 2011. Amsonias look great planted in masses. Flowers attract butterflies, and deer don’t seem too interested.

The blue flowers of Amsonia float at the top of thread-like foliage.

This Amsonia is just beginning to show hints of fall. In a few weeks, it will be a mass of butter-yellow leaves.

Flower Timing Dictates Shrub Pruning Schedule

February usually has a few unseasonably warm days, teasers for the spring weather that is still weeks away. Use those days to start on spring gardening chores. I once named Valentine’s Day as the target date for pruning my hybrid tea roses and other summer- flowering shrubs. I no longer struggle with roses (beautiful, but too time-consuming and disease-prone in my hot, humid garden) but mid-February is still a good time to consider pruning.

Broken, damaged or crossing limbs can be removed any time of the year. Prune summer- or fall-flowering shrubs (Gardenia, Beautyberry, Crape Myrtle, Butterfly Bush, Tea Olive) in late winter, before spring growth begins.

For shrubs that bloom in spring (Azalea, Weigela, Forsythia, Lilac, Spirea, Mock Orange), wait until after flowering is over, then prune. Any pruning done in late winter will remove dormant buds and eliminate some or all their flowers.

While it is unlikely that you will kill a shrub by poor pruning, it is possible that the result will be so unattractive that you wish the plant would die. Even if you got a pair of shiny new pruners for Christmas, have a specific result in mind (renewal, size reduction, shaping, thinning, increased flowering) before you start cutting. Refrain from mindless trimming.

Select shrubs whose mature size will fit into your border or foundation bed. When I worked in a garden nursery center, a vein bulged in my forehead every time I heard a shopper announce that they were going to purchase a shrub too large for the intended location and say, “I’ll just cut it back every year to keep it small. It will look okay.” Please, I implore you, do not be that person. Because you won’t. In five years, the shrub will either have outgrown its space or its natural shape will be lost by excessive pruning. Butchered plants look horrible.

To obtain privacy from a dense hedge, start pruning when plants are small. Use hand pruners to cut back the tips of each branch. This will make dormant buds along the stems wake up and produce new branches. Repeat this tip removal as needed to encourage additional branching until the hedge is approaching the desired mature size. Informal, loose hedges are easier to maintain than tight shapes, but a sharply-edged hedge gives a lovely, formal appearance. You can use powered (electric, gas, battery) hedge trimmers to trim hollies, boxwoods, Ligustrum and similar shrubs into tight shapes, but always cut at a slight angle so that the top is narrower than the bottom. When done properly, this allows sunlight to reach the lower leaves as well as the upper ones and prevents leaf-loss near the ground. The angle does not need to be exaggerated to be effective – think of the bottom half of the letter A.

Think twice before planning a formal, tightly pruned hedge of Azalea, Forsythia, or Loropetalum. These plants look best when allowed to maintain their open, spreading shapes. Restricting them into a narrow strip will require frequent trimming and result in reduced flowering.

Conifers respond poorly to hard pruning. Yew, juniper, and Arborvitae rarely break new growth from old stems. Light tip pruning is okay. Remove dead or damaged branches; otherwise, leave them alone. For broadleaf shrubs like Aucuba, avoid cutting large leaves. Instead, reach loppers to the interior of the shrub to make cuts, removing entire branches. This will increase airflow and allow sunlight to enter the interior. Boxwoods, a staple of many southern gardens, look their best and are healthier when pruned this way.

Hydrangeas require special attention to pruning. Those that bloom on new growth (‘Incrediball’ or ‘Limelight,’ for instance) should be pruned in winter. Those than bloom on old growth (oakleafs, many of the old-fashioned mopheads) should be pruned immediately after flowering. Some, known as rebloomers (‘Endless Summer’™ types), bloom on both new and old growth. If you plan to add a new Hydrangea to your garden, purchasing a rebloomer will ensure that you still have some flowers if a late freeze zaps buds that have already started to open. What if you don’t know which cultivar of Hydrangea you have? Leave them unpruned one season and pay attention to where the flowers occur. Use this information as your guide for future years.

When using hand pruners or loppers, prune just above a bud. In this case, “above” means between the bud and the tip of the stem (not between the bud and the end of the stem that meets the ground.) Don’t leave too much stem between the bud and the cut, or the stub will die. Don’t cut too close to avoid damaging the bud itself. Make an angled cut near the bud (between the bud or stem). New growth will angle off the pruned branch in the same direction as the bud. See the photos for an illustration.

Too far from bud leaves stub

Too close damages bud

Just right!