Coneflowers

'Showoff' Echinacea at Kingwood Center, Mansfield, OH

Coneflowers (Echinacea spp.) have undergone great improvements over the past quarter century. Varieties are now available in many color shades and plants flower for longer periods. Recently introduced cultivars also grow alot shorter. On the negative side, some hybrid forms have been disappointing, barely surviving 1-2 years in the garden.

For overall dependability, Purple Coneflower (Echinacea purpurea) is my #1 favorite for dependability (USDA hardiness zones 3-8). The species is native to most of the Eastern and Midwestern U.S. They bloom in July, August, and into September, their nectar-filled flowers attract  butterflies and bees, and their winter seed heads provide food for birds and other critters.

Yellow Coneflower (Echinacea paradoxa) is native to the Ozark region in Missouri and Arkansas. The yellow blooming E. paradoxa have been bred with E. purpurea. Flowering starts in June, and puts on a long show even as the petals fade. This species has a small geographic range due to habitat loss.

Pale Purple Coneflower (Echinacea pallida) are native from the central U.S. Petals tend to be long, narrow, and droopy along with washed out lavender color. Leaves and stems are particularly fuzzy. They bloom from June to July and grow in most U.S. gardens under proper care.

Tennessee Coneflower (Echinacea tennesseensis) are native the state, but their habitat has been in decline over the past half century. Only recently has it been removed from the endangered species list. This mid-summer bloomer grows 2 to 2 ½ feet tall.

Coneflowers perform best in full sun and within a low to moderate range of soil fertility. While good soil drainage and watering during prolonged dry spells are good practice. Keep in mind that most coneflowers establish deep taproots and resent constant irrigation and over-feeding. To insure winter survival, coneflowers should be planted before July 1st.

'Thunderhead' Japanese Black Pine

Thunderhead Pine

'Thunderhead' (Pinus thunbergii) is a choice shrub selection of Japanese Black pine. This medium-sized evergreen shrub conifer grows 10 to 12 feet high and 12 to 15 feet wide (in 10 - 15 years). Its distinctive cottony terminal buds and dark green densely packed needles are strikingly beautiful in the fall-winter landscape.

“Billowy emerald clouds of densely packed needles” best describes the overall look of Thunderhead pine.  Silvery white candles (shoots) grow 10 - 12 inches long in response to warm spring temps.  The candles reach their full length by late May and the long bright green needles enlarge. Branches are rigid and its lower needles are mostly retained.

Disease and pest problems are rare when sited properly in the landscape. Thunderhead is tolerant of moderate wind, drought, and salt spray. Provide shelter from harsh winds to minimize off-color in winter. Availability is primarily from specialty conifer nurseries on-line or regional conifer nurseries.

Desired location is moderately acidic soils that are well-drained and in full to partial sun. Provide a minimum of 6 hours of sunlight. Plant in late winter to early fall from container or balled and burlapped (B&B) stock. Feed annually in late winter with 10-10-10 or equivalent granular fertilizer. Allow 1-2 years to become established after planting; hence forth drought and heat tolerant.


Pruning is rarely necessary except for desired shaping and sizing; cut back new shoot growth (“candles”) between late May to early June before needles are fully expanded.

Thunderhead Japanese black pine a wonderful low maintenance, dark green, evergreen shrub conifer that deserves a place in your landscape.

Growing Siberian Iris

'Caesar's Brother'

Siberian irises are favored by many gardeners  over the more popular bearded irises for their ease of maintenance, longevity, and disease and pest resistance. Their flowers are smaller than bearded iris blooms, but their grass-like foliage looks attractive all season long. Siberians are also more cold and heat tolerant.

Siberian irises are mostly hybrids of two southwest Asian species, I. sibirica and I. sanguinea (USDA hardiness zones 3-9). The narrow, grass-like foliage forms a vase-shaped clump to 2 feet high. Autumn foliage turns rusty brown in late fall. Flowering stems rise above the foliage to 3 feet tall in May-June.

Siberians perform well in most garden soils, but are at their best in humus-rich, mildly acidic soil. In spring feed with 10-10-10 or an equivalent granular fertilizer. In early summer apply a water soluble fertilizer such as Miracle-Gro™ or Jack’s™.

In Northern states (zones 3-6), Siberians want full day sun (or 6-hours minimum). In Southern areas, shelter from the mid-afternoon sun. Ample spring moisture is key, along with adequate rainfall during the summer. These iris clumps tolerate moderate summer dry periods of a week or two.

Mulch iris in spring to conserve soil moisture and prevent weed infestation. Voles and mice may munch on rhizomes. Remove spent bloom stalks, and brown and withered leaves to keep planting looking attractive. In late fall cut back all leaves 1-2 inches above the ground.

Siberian irises are generally pest-free with very little susceptibility to the two main problems of bearded iris, namely iris borer and bacterial soft rot. Plants tolerate deer and rabbits.

Divide big healthy clumps into 2-4 fans in either late summer or fall, depending on where you live. In northern zones spring or late summer are the best time to plant or divide. In southern climes, early fall is a better time. Clumps can grow undisturbed for several years, unless they become crowded, plant vigor declines, or bloom size declines.

Over 200 varieties are available, principally from online iris nurseries.

Dwarf Forms Of Elkhorn Cedar (Thujopsis)

Elkhorn cedar (Thujopsis dolobrata) is a slow to moderate growing evergreen shrub or tree. It is also called Hiba or false arborvitae and deerhorn cedar, referring to the shape of its scale-like leaves. It is rarely grown in U.S. gardens (USDA hardiness zones 5-7).

Thujopsis 'Aurea'

This native of Japan and China has a pyramidal growth habit and beautiful dense foliage similar to arbovitae (Thuja spp.). Mature trees may reach 50 -100 feet in height in the Japanese woodlands.  

The scale-like bright or dark green leaves are arranged in flattened sprays with white markings beneath.  Its reddish-brown peeling bark adds to the plant's appeal.  Small 3/4 inch cones provide little ornamental value. 

False arborvitae grows best on a moist well-drained site in full sun or bright shade . Occasional watering is recommended in severe summer/fall dry periods. False arborvitae needs to be sheltered from dry winter winds.

Winter foliage color may vary by location and cultivar planted. Here in the Southern Appalachian Region (USDA zones 6 and 7), winter foliage takes on a muted olive-green tone.

Two dwarf clones are:

• 'Aurea' - a dense shrub with golden yellow foliage; grow in light shade.
• ‘Nana’ - a slow growing, dwarf mounding form with good plant symmetry. Its wintry foliage takes on a silvery tint.

A 10-year old 'Aurea' or 'Nana' thujopsis grows 3 to 4 feet tall and 5 to 6 feet wide. 

False arborvitae is hard to find in the nursery trade, but are available thru e-commerce specialty nurseries.

New Popularity Of Yellow Twig Dogwood

Red osier dogwood (Cornus sericea) is a medium-sized, deciduous shrub native to much of the Northern and Western United States (USDA hardiness zones 2-7). These shrubs standout in the winter landscape by their colorful stems. Cut branches are an added plus for indoor arrangements.

In recent years the yellow-twig form (C. sericea 'Flaviramea') has gained in popularity. Osier dogwoods grow well in very large containers, but can rapidly outgrow their pot space in 2-3 years.

Leaves are oblong-lanceolate (up to 5 inches long), oppositely arranged with 5-7 pairs of lateral veins, and entire margins. Species may grow up to 10 feet tall and spread voraciously by underground stolons to form large clumps. One landscape idea is to mix red and yellow–twig dogwoods together for an added color blast.

These stoloniferous dogwoods bloom in mid-spring (in Tennessee and Virginia). The terminal creamy white (cyme) flowers measure 1.5 to 2.0 inches across and white berries follow in late summer.

In northern areas, plant osier dogwoods in full sun (Zones 2-6) and in partial shade (Zone 7). Shrubs handle average soils. Fertilize in early spring before buds break and irrigate during long dry summer spells. Shrubs establish quickly and become drought tolerant after one year.

Stoloniferous dogwoods are disease and insect resistant and deer generally overlook them. Utilize them in perennial or shrub borders, masses and groupings, container gardens and winter gardens.

Pruning tip: cut 2-3 year old shoots back to the ground immediately after spring flowering to promote colorful juvenile shoots.

Korean Sweetheart Tree

Bright Red Fruits of Sweetheart Tree

The late Dr. J. C. Raulston, N.C. State University horticulture professor emeritus, discovered Korean sweetheart tree in 1985 on the Korean Peninsula while participating in a U.S. National Arboretum collection expedition. 

Dr. Raulston brought seeds back to the N.C. State Arboretum for assessment and evaluation. The common name "sweetheart tree" was coined by Tennessee nurseryman Mr. Don Shadow.

The tree prefers a sandy or medium loamy soil and full sun to partial shade. Once established the tree tolerates brief dry periods lasting 4-5 weeks, and is at its best in soils with consistent and even moisture. Provide supplemental irrigation in regions where summers are exceptionally hot and dry.

Opposite pinnately compound leaves measure 6-10 inches long. The fruits are major asset for this small growing tree/large tree. In late summer showy clusters of heart-shaped fruits ripen from green to pink to red. In early to mid-October the fruit capsules split open to reveal a tiny, shiny, black seed.The grayish colored bark has white striations which adds some winter interest.

No serious disease and insect problems trouble this small 25-30 feet tall tree. Availability is primarily from on-line plant nurseries