Archive for July, 2013

Summer High Fives

Summer High Fives

Bring a winning team to your summer garden with summer shrubs. More color. Less maintenance.

By Deb Terrill • July/August 2011

If spring blooms are a symphony, they may be compared to the first movement of Beethoven’s Fifth. They arrive with
exclamation and quickly reach a swelling crescendo. Summer bloom is more like the second movement, quietly beautiful, with flourishes of majesty. Fortunately, we have a nice selection of summer-flowering plants, from beauty bush to hydrangea, that can keep the music playing all season long.

Beauty Bush
The earliest of the summer bloomers, flowering in late May and June, include beauty bush (Kolkwitzia), which is a relative of honeysuckle. Hailing from China, this large pink-flowered shrub has an arching habit and when in bloom, it looks like pink tracers falling from a fireworks display. The shrub suckers freely, much like honeysuckle, but is not invasive. Like most summer bloomers, you will want to give this old-fashioned shrub plenty of room to grow in order to preserve its natural habit and beauty.

A new cultivar of beauty bush, called Dream Catcher™, stays slightly smaller at 6-8 feet and has vivid yellow leaves on reddish stems throughout spring. The fall color is golden yellow and this lovely cascading foliage needs a little more protection from sun. Place it where it can brighten up a semi-shady corner of the mixed border.

A Trio of Natives
Among a few natives with summer bloom, bottlebrush buckeye (Aesculus parviflora) is the earliest and showiest as well. This shade lover forms a loose, airy clump of woody stems that give rise to long, wispy “candles” of white bloom. The more diminutive summersweet (Clethra alnifolia) also bears wispy white or pink flowers and has outstanding yellow fall color. Give it damp, slightly acidic soil and it will perform beautifully. If your soil tends more to drier alkalinity, consider the Virginia sweetspire (Itea virginica). There are many cultivars of this plant, which is known more for its vibrant red and orange fall color than its small, brush-like white or pink flowers. All three of these natives attract bees and hummingbirds.

Rose of Sharon
Althea, or rose of Sharon (Hibiscus syriacus), is one of the very few summer-flowering shrubs to offer large, showy blooms at a time when most shrubs have become background notes. These outstanding beauties are under appreciated as they are very easy to grow and are now available in a color range that includes bubble gum pinks, bright whites and true blues. Keeping them deadheaded will prevent unwanted seedlings.

Another shrub, less showy but equally valuable, is the misunderstood smoke bush. Unlike other summer bloomers, this one may be heavily pruned to fit any space and rewards the attention with more bloom. A newer cultivar called ‘Young Lady’ stays small and has such heavy bloom as to appear like a cloud of green smoke tinged in purple. It is absolutely unique in the genus and has become a personal favorite.

Hydrangeas for Every Situation
Hydrangeas are rightfully the most popular among the summer shrubs and the number of choices here can be staggering. Plantsman David Cook of Art’s Landscaping in Bourbonnais is just the man to help sort through the possibilities. Pressed for a hand’s down favorite, David named Quick Fire™, one of the large paniculata group that includes ‘Limelight’, ‘Pinky Winky’ and Vanilla Strawberry™.

“I love the vibrant color of Quick Fire’™ says Cook. It’s the earliest to bloom and starts out with an intense red edge that only gets better with time.” Cook says Pinky Winky™ is nice too, but has a softer pink, less substantial bloom, and is not as strong and robust. Vanilla Strawberry™ has a sort of cherry blossom effect, with a football-shaped inflorescence of white flowers fading to baby pink. The stems appear strong enough to hold the blooms upright as well.

‘Limelight’ is another Cook standby. “It just needs plenty of room. People don’t realize how large it gets and don’t give it enough space to explode,” says Cook. “It’s fabulous when allowed to grow. When space is an issue, Little Lime™ is a good alternative, but even it gets to be 5 feet tall.” Cook thinks gardeners try to give paniculata types too much shade and too little space. “They can take full sun and need it to flower the way you want them to.”

Cook says giving the mophead types (H. macrophylla) room to grow will increase blooms on these sometimes stubborn shrubs as well. “A protected exposure and minimal pruning—only to deadhead spent blooms and remove dead or broken wood—is the key to getting blooms from mopheads like ‘Endless Summer’. You simply can’t be cutting them back to the ground and then expect them to perform.”

Incrediball® is a new selection of the old-fashioned ‘Annabelle’ in the H. arborescens group. Cook is very enthusiastic about it, saying “the stems are sturdier than ‘Annabelle’, so it doesn’t flop nearly as much. And while I don’t care as much about flower size, it really does have blooms like a basketball.” A group of Incrediball® hydrangeas that he planted four years ago have grown to about 4 feet by 4 feet and “they are not flopping at all.”

Hydrangea arborescens, like ‘Annabelle’, Incrediball® and Invincibelle® Spirit (the pink ‘Annabelle’ that raises money for breast cancer research) can also take full sun, but Cook says there is a trade off. “Arborescens types bloom better with more sun, but they need supplemental water. The soil must be moist to keep the leaves from hanging down in the mid-day heat. Even those in shade, with moisture, will flag on a really hot day.”

At his own home, which has very limited space, Cook favors the oakleaf group of hydrangeas. ‘Little Honey’ is wildly exciting, he says. “It needs shade to protect the leaves from burning, but this dwarf oakleaf has really yellow foliage and turns the most amazing shades of orange in the fall.” The flowers are not showy, but the foliage really lights up a dark, shady area. “I love, love, love it!” Cook also grows ‘Sikes Dwarf’, ‘Pee Wee’ and the species oakleaf (Hydrangea quercifolia) for their soft, natural blooms and showy red foliage in the fall. “These are subtle beauties, and not to be beat for naturalizing.”

When asked for his best tips for growing hydrangeas beautifully, Cook offers the same mantra, “Give them room; they’re large shrubs.” He also says they would all benefit from more water and “I wouldn’t even attempt to grow hydrangeas under trees with heavy root competition. It’s not worth the struggle.”

Pruning Hydrangeas

Most hydrangeas don’t need pruning at all except to remove spent flowers and dead or broken stems. If yours have become too large for the space, then you may want to prune them to reduce the size. Be especially judicious about removing any stems the first three years after planting. Hydrangeas can be weakened by severe pruning when they are young.

  • If you have ‘Annabelle’ (Hydrangea arborescens) or ‘Pee Gee’, ‘Tardiva’ and ‘Limelight’ (all Hydrangea paniculata cultivars), you have hydrangeas that bloom on new growth. These may be pruned back severely in late winter (March), just before bud break. The spent flowers can be clipped off anytime.
  • Cutting these back to the ground every March is not advisable, though, because removing all stems every year will not allow any stems to become thick enough to support the plant and its heavy blooms. To add some structural integrity, leave one-third of the thickest stems at a height of 2 to 3 feet. This will help keep the plant from being too floppy.
  • Oakleaf hydrangeas and macrophyllas, the kind with shiny, leathery leaves and purple or blue flowers, may bloom on old stems, or on both old and new stems (‘Endless Summer’). Prune these only in summer months (June and July) to avoid cutting off stems that have already formed the next year’s flower buds. These should be pruned conservatively, leaving older stems whenever possible. Always remove dead stems.
  • You may clip off spent blooms anytime of the year, but prune oakleaf and macrophylla hydrangeas by removing only a few full stems (less than one third) or by cutting the stems back by only one third of their length. This essentially means trimming for shape rather than cutting the whole plant back. And remember, this is best done in June and July.
  • If you want to renovate the shrubs, you can cut them back to a foot or so from the ground, but you will likely have few, if any, blooms the following year. This should be done only when you need to reduce the size of the plant.
  • Remember that hydrangeas can become quite large, so situate them where they can expand without constantly being headed back.

July 5, 2013 at 9:55 AM Leave a comment

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