Wednesday, January 1, 2020

New Osage Orange Trees Are Gamechangers

Osage Orange replaced with thornless, fruitless varieties
Osage orange (Maclura pomifera) has been declawed and neutered (USDA Zones 5-9). A member of the mulberry family (Moraceae), this tough prairie tree species is native to south Central states. The medium-sized 35-40 foot tree grows fast @ 2 ½ to 3 feet per year. It is also called Bois D’Arc (pronounced “bow-dark”).

‘Wichita’ and ‘White Shield’ are fruitless and thornless (male) selections. Both cultivars develop into attractive landscape trees with deep green shiny foliage that turns a beautiful fall pale to golden yellow in fall. ‘Wichita’ grows slightly taller than ‘White Shield’, and its branching is slightly more upright.  ‘White Shield’ forms a rounded canopy, averaging 35 feet in height and spread.  Mostly inconspicuous tiny green flower clusters appear in late spring.

Osage orange, aka "hedge apple" is a dioecious species. Male trees make effective landscape shade trees. Female trees are generally not recommended for landscape use because their fruits pose a considerable litter problem. Mature tree bark is deeply fissured, with an orange-brown inner wood peeking through. In the early years, pruning helps to develop a well-branched tree.

Hedge apples, i.e. large 4-6 inch wide yellowish green fruit, weigh 2 to 3 pounds each. Fruits on female trees fall from the tree in October and are a huge maintenance headache. Female trees need a male tree pollinator in order to produce fruit.

Fierce ½- inch long thorns, hidden within the dense branches, can do lots of harm, even puncture a vehicle tire. The tree’s wood is hard and does not split easily.

Osage orange is easily grown in average, dry to medium, well-drained soils in full sun to part shade. The tree grows almost anywhere, in poor infertile, acid or alkaline soils, and dry or wet fields. It also tolerates drought, heat, cold and wind. Disease and pest problems are practically non-existent. Its foliage is tolerant of urban air pollutants.

Both cultivars are good choices planted on large residential or commercial properties, city parks, and golf courses. Also, plant under high power lines or utilize as a deciduous windbreak.

Sunday, December 1, 2019

Red Dragon™ Contorted Filbert


Red Dragon filbert in Columbus, Ohio garden


Red Dragon™ is an outstanding red leaf selection of contorted filbert (C. avellana Red Dragon™). This unique landscape shrub grows 6 - 8 feet tall and 5 - 6 feet wide. It is a perfect size for most urban gardens (USDA hardiness zones 4-8).

This red-leaf shrub was developed by the Oregon State University filbert breeding program. Currently, gardeners are losing the popular green leaf variety "Harry Lauder’s Walking Stick" (C. avellana ‘Contorta’) to Eastern filbert blight. Red Dragon filbert demonstrates superior resistance to this disease. It also replaces ‘Red Majestic’, another red leaf variety also susceptible to Eastern filbert blight.

Red Dragon grows best in moist, organically rich, well-drained soil and in full sun to partial shade. It tolerates average garden soils. Prompt removal of root suckers improves shrub appearance by avoiding a buildup of thickets.

Autumn leaf drop exposes the unique contorted branching and ornate floral catkins in early days of spring. Filberts are monoecious, e.g. individual male and female catkins (flowers) develop on the same plant in late winter to early days of spring (March-April) before leaves emerge. The 2-3 inch long yellow male catkins (flowers) are showier. The 4-inch elliptical or ovate leaves are doubly serrate.

Red Dragon retains its burgundy red leaf color into early summer. The foliage is also partly curled. Leaves are coated with tiny hairs and appear dusty by the end of summer. Fall leaf color is variable, often with tinges of yellow. Smooth light bark is gray-brown.

Nuts appear in terminal clusters of 1-4 and are half covered in ragged husks. Nuts ripen in late August and September which the neighborhood squirrels and birds should enjoy.

Red Dragon filbert may also be grown in containers. Disease and pest problems are few. Japanese beetles may vigorously attack the foliage in some areas. Scale may also occur.

Red Dragon™ is mostly sold grafted and available from specialty nurseries online. It requires little to no pruning; remove root suckers and keep the shrub well mulched. ‘Red Dragon’ is sold either grafted or not. It is sold primarily by online nurseries.

Saturday, November 16, 2019

Small Leaved Anise

'Florida Sunshine' anise at Milliken Arboretum in Spartanburg, SC

In recent years there has been lots of interest in the anise (Illicium) shrub group. Anise shrubs (Illicium spp.) are fast growing, evergreen shrubs (USDA zones 7 to 10). They exhibit a multi-stemmed, upright, compact form. Their green foliage  is quite attractive and aromatic, the odor similar to anise spice when crushed. Their shiny, leathery leaves are olive green in color and the 1.5 inch wide flowers are dark red and appear in early spring.

Yellow anise (Illicium parvifolium), aka small anise, is a Southeast U.S. native. Popularity has soared with the introduction of gold leaf cultivars like 'Florida Sunshine' and Banana Appeal®. The cultivar 'Florida Sunshine' grows only 7-8 feet tall. Both cultivars are more tolerant of full day sun and dry soils. Their gold color becomes sharper over the winter months

In the wild, species shrubs eventually grow 10 to 15 feet tall and should be spaced at least 5-6 feet apart in the landscape. Their natural habitat is in the wet, swampy areas or along wooded streams in humus-rich  acidic soil from Florida to Louisiana. However, newer varieties have demonstrated winter hardiness further north into (zone 6) parts of Tennessee, Carolinas, and Virginia.

Illicium grows in partial to full shade, but reportedly will acclimate to full sun if irrigated. The anise shrub world is changing. Watch for new cultivars arriving at local garden centers.



Friday, November 1, 2019

Kentucky Coffeetree

Kentucky coffeetree (Gymnocladus dioicus) is a large native tree found in 18 states, from New York west to Nebraska and from central Minnesota south to Oklahoma (zones 4 through 7). It averages a mature height between 60- 70 feet (some greater than 90 feet) with a spread of 35-50 feet. This tap-rooted tree establishes within 2-3 years, with an annual growth rate averaging 12-15 inches, about the same as ginkgo or white oak.
Kentucky coffeetree

Spring leaf out occurs in mid- to late spring. Recessed vegetative buds push forth as multi-pinnate compound leaves. A single leaf may measure 2 to 3 feet across, producing between 70 and 100 leaflets. Fragrant olive-white flower panicles appear in late May in clusters of 8 to 12 inches long by 3 to 4 inches wide.

In autumn its lime-yellow to golden brown compound leaves drop to become a leaf raker’s nightmare. During the winter months, the totally naked upright branches take on a stark appearance. K-coffeetree may be single or multi-trunked.

K-coffeetree grows in a wide variety of soil types and tolerates a poorly drained wet sites. No significant disease or insect pests mar the lush green tropical-like summer foliage. Bark is distinctively charcoal gray and shaggy, a trait more pronounced as the tree ages.

Spring pea-like flowers are dioecious, bearing either male or female flowers. Female trees bear clusters of broad bean pods measuring 5 -10 inches long and 1 ½ - 2 inches wide on the tips of branches. Flowers and pods are inconspicuous, mostly hidden within the dense foliage through late summer.

'Espresso' is a male cultivar with no seed pods to rake up. In colonial America the beans were harvested and a crude coffee extract was brewed, no threat to Starbucks. The leaves and bean seeds are reportedly toxic to man and grazing cattle.

K-coffeetree is rarely sold in garden centers, but is available from on-line nurseries. Notoriously difficult to transplant, young 2-inch caliper nursery-grown trees move easily.

Tuesday, October 1, 2019

'No Dig" Bulb Planting



"No Dig" Planting of 'Pink Perfection' Tulips
Digging all the holes to plant 25, 100, or 500 tulip bulbs can be a backbreaking chore. It doesn’t have to be that way. 

More than a decade ago, plant researchers at Cornell University in Ithaca, New York, developed a planting method called “top-planting”. It eliminates all the digging and the tulips come back and bloom well for several years.

Top-planting, also called “drop and cover,” is a planting technique that requires a lot less effort.

No Dig bulb planting is a lot simpler:


·         Choose a site in full sun and good soil drainage.

·         Till the planting area 3 to 4 inches deep with a roto-tiller.

·         Spread bulb fertilizer and lightly till in the fertilizer (optional).

·         Set the bulbs on top of the tilled area (no need to press the bulb into the ground).

·         Cover with 2 to 4 inches of composted mulch or aged compost.

·         No Dig works as well for daffodils as tulips.


Do not over-mulch. Adding more mulch will result in less blooms. Any good garden compost or double ground bark mulch should work. Brent Heath with Brent and Becky’s Bulbs in Gloucester, VA recommends adding  two inches of mulch in the fall of each year.


Bulb Spacing: Tulip (or daffodil) bulbs should be spaced 3 times the bulb size or 6 inches apart. That’s 4 bulbs per square foot.


Tulip varieties that perennialize well are recommended, particularly Darwin hybrids. They will regrow and re-bloom for several years. Again, don't forget to add 2-3 inches of new pine bark chips or pine needles to replace depleted mulch additions from past years.

Caveat: dormant tulips and daffodils like to spend their summers in dry soil. Too much irrigation during the summer months may rot the sleeping bulbs.


Sunday, September 15, 2019

'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.

Sunday, September 1, 2019

Katsura Tree


'Pendula' Katsura tree
Hooray! In American gardens Katsura tree (Cercidiphyllum  japonicum) is finally becoming more planted as a fine landscape tree. There are a number of great varieties to choose. This medium to large growing tree (height depending on cultivar) commands four-seasons appeal. Rated as a medium-sized 40-60 foot pyramidal, this long-lived majestic specimen may top off at 75 feet in height before its first 100 years. 

Its beautiful heart-shaped soft green summer foliage transforms to purple and gold shades in autumn. After the leaves fall they reveal its lovely symmetrical branching and scaly/shaggy bark. Often, the fall air holds a cinnamon scent reminiscent of cotton candy or a sugar-cookie.


Katsura tree is indigenous to Japan and China where it can grow an incredible 100 feet tall (USDA hardiness zones 4-8). The species is dioecious, e.g. separate male and female trees. The tiny flowers are mostly inconspicuous and small pods with numerous winged seeds are dispersed by female trees in late fall. Katsura tree is also not invasive.

Select Cultivars: some 20 varieties are listed, but I mention only 4 here:

'Pendulum' – lovely weeping form 15 to 25 feet tall and 20 to 25 feet wide. Other weeping forms also lumped as 'Pendula'.

‘Morioka Weeping’ - another weeping form, 20 feet tall and 15 feet wide, with more upright growing branches when young and  large leaves.  

‘Red Fox’ (‘Rotfuchs’) – 30-foot pyramidal tree; new spring reddish purple foliage, turns dark bronze-green in summer and orange-bronze fall color.

‘Claim Jumper’ - a relatively new gold-leaved variety that grows 25-30 feet (8-10 m) and 20 feet wide. Leaves emerge with a pink blush and unfurl to soft golden-yellow. Gold leaf color fades away by late summer.

Katsura tree is easily grown in a moist well-drained soil and in full sun to part-shade. Growth rate is equal to a sugar or red maples. Newly planted 1-2 year old trees are particularly prone to leaf scorch. During its first year or two after planting, katsura is susceptible to long dry spells and will need irrigation in periods of no significant rainfall.
Katsura are rarely troubled by serious pests or disease problems. Katsura tree and cultivars are sold at full-service garden centers, but smart gardeners are likely to quickly buy up the inventory. Rare or new cultivars, like some that are listed here, are sold by on-line specialty nurseries.