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.