Waxbells, as Kirengeshoma palmata is commonly called, is an herbaceous perennial with a shrublike habit that adds striking foliage and sweet pale yellow flowers to the late summer shade garden. The flowering display begins in mid August and continues through September. Earlier in the season, the large maple like leaves add bold contrast to the many delicate textures that predominate in our beds. Kirengeshoma may be a little late to break dormancy in the spring, since the new shoots are quite frost sensitive, but once it finally feels the weather is safe, it quickly grows to a height of 4-5′. With time, plants form large clumps 3-6′ across. And if you need another big plus, the deer dislike it.
Kirengeshoma is native to the woodlands and low mountain regions of Japan and Korea, which accounts for its hardiness through zone 5. It grows best in a rich, slightly acidic soil that is moist yet well drained. Propagate by seed or by division in early spring. We like to associate Kirengeshoma with blue and gold Hosta, such as ‘Deep Blue Sea’ and ‘Brother Stephan’ as well as late blooming Actaea ‘Hillside Black Beauty’ .
Sometimes your garden needs something tall, something blue. The abundant display of summer perennials laden with yellow daisy-like flowers begs for plant selections which offer dark contrast.
A “temperennial” here in zone 6, Tall Mexican Petunia won’t winter over outdoors for us, but it certainly will in zones 8-10. Still, we always make room for it in our gardens and also use it in container combinations where the tall 3-4′ purple stalks are clothed with narrow dark green purple tinted foliage. The continuous display of violet blue funnel shaped flowers extend on short stems from the leaf axils, and attract bees, butterflies and hummingbirds.
Ruellia ‘Purple Showers’ does enjoy evenly moist soil, and will even grow well along a pond?s edge or in low standing water, a situation that can be challenging. This does not mean it won?t grow in average soil conditions, for it will, but it does not want to fry. Southern nursery catalogs list Ruellia as an evergreen shrub. We suspect Ruellia may become territorial in warm climates, and should be planted where its vigor is an asset.
Not all Persicaria deserve persecution. Persicaria amplexicalis ‘Golden Arrow’ is not only one of the “good” members of the Polygonum (Knotweed) family, it is an extremely handsome and versatile perennial. The first thing you should note is the golden green lance shaped foliage, which is attractive all season. Big plus. In mid summer ‘Golden Arrow’ begins to display an array of ruby colored spiky tassels, which account for its common names: Firetail and Red Bistort. The flower show continues into September, and both flowers and foliage combine beautifully with the many late summer yellow composites, as well as pink or blue/violet asters, and of course all the Salvia.
Leaf color is brightest yellow when grown in full sun, but ‘Golden Arrow’ will require a little extra moisture if the area is on the dry side. Otherwise, grow it in a well drained soil in half day sun, where the golden yellow will tint slightly more green. Foliage height reaches 18-24″, with flowers adding another 6″ or so to the plant’s stature. The spread of each plant depends on age and culture, but expect Persicaria ‘Golden Arrow’ to eventually take up 2 sq. ft. It grows well in a wide range of hardiness zones from relatively mild zone 9 through a quite chilly zone 5.
Hayes Starburst Hydrangea is a floral arranger’s dream. This chance discovery, by Hayes Jackson of Anniston, Alabama, differs from the species by its showy display of clustered greenish white, multi sepaled star shaped flowers. It is a form of Hydrangea arborescens, also known as Smooth Hydrangea or Hills of Snow, and although native to the southeastern U.S., is cold hardy into zone 4.
Hydrangea arborescens ‘Hayes Starburst’ blooms on new wood, so there is little danger of winter damage to flower buds. We recommend cutting back the woody stems to 12″ in early spring to keep the plants tidy. Hydrangea arborescens prefers to grow in full to half day sun and in a well drained soil that still gets adequate moisture. If there is a common complaint about this species it would be that the flower clusters are so heavy that they weigh down the supporting stems. Some consider this an addition to the plant’s charm, and if it is sited on a slope or above a retaining wall, you could take advantage of its cascading habit. If an upright habit is preferred, situate a large tomato cage over the cut back stalks in spring, which will lend support. The height and spread of this shrub can remain a manageable 3′ x 3′, if pruned annually.
First, we fell in love with the foliage. The new foliar growth is a delicious shade of caramel pink, gradually becoming lime green as the summer progresses. As the July heat intensifies, 4-6″ panicles of white pearly buds burst into creamy Astilbe like plumes. Sorbaria sorbifolia ‘Sem’ is a compact growing False Spirea, growing only to 48″, unlike the species which can reach 8′ or more. ‘Sem’ will give you moderate height without obscuring your view. Yes this form will sucker and form a thicket…but that is why you should use this shrub as a low hedge, or for filling a space that you don’t want to fuss over.
Here are the other pertinent facts: Sorbaria ‘Sem’ grows in full sun or part shade, is deer resistant and is hardy to minus 35 degrees F. Pretty and tough, don’t you think?
Gardeners in northern climates have been disappointed by Hydrangea macrophylla in the past….lots of healthy foliage, but few or no blossoms. This recent introduction of Mophead Hydrangea truly blooms on both old and new wood, and is being marketed as ‘Forever and Ever Red Sensation’ ( Tra-la-la…those clever marketers read a lot of fairy tales).
What you really need to know is that this vigorous selection produces lots of blooms on new growth, making it a great candidate for colder zone 5 and 6 gardens. In hot climates the large trusses of blossoms will be in softer shades of rosy pink when grown in neutral to slightly alkaline soil. Colder temperatures will cause the flower color to deeper red shades. If your garden soil happens to be more acidic, ‘Red Sensation’ will change color and thus need a new name, as it will take on bluer tones. The flowers age to smoky violet. Stems and fall foliage color have a dark burgundy cast.
‘Red Sensation’ grow 2-3′ tall and 3-4’wide, and require full sun or partial shade. Hydrangea macrophylla appreciate a moist, rich and fertile soil. May we suggest combining ‘Red Sensation’ with the always attractive Periscaria ‘Golden Arrow’?