What Grows There :: Hugh Conlon, Horticulturalist, Garden Advisor, and Photographer

Contorted Filbert Offers Great Fall And Winter Interest

Posted by Hugh on March 23rd, 2012

Catkins of Harry Lauder's Walking Stick

Contorted filbert (Corylus avellana ‘Contorta’), aka Harry Lauder’s walking stick, is an 8-10 foot tall shrub. It grows in average well-drained acidic or mildly alkaline soil and thrives either in full or partial (6 hours) sunlight. Contorted filbert is usually sold in a grafted form.

It is also called corkscrew hazelnut because most branches, twigs and leaves display a twisting or spiraling nature. Showy yellowish brown male catkin flowers grow to 2-3 inches in length in late winter and early spring. Tiny female catkins are barely visible. Contorted filbert does not bear fruits (nuts).

The light green almost circular leaves (2-3 inches in diameter) are double-toothed along the leaf margin. The foliage turns a drab yellow in the fall. Following leaf abscission, the curlicue branching provides considerable autumn and winter interest.

Contorted filbert has no serious insect or disease problems. Susceptibility to crown gall is often associated with a poorly drained site. Occasional scale insect infestations may be eradicated with 1-2 applications of dormant oil in the winter months before new leaves emerge. Root suckering may become a maintenance nuisance. These straight growing (not twisted) suckers tend to eventually dominate the entire shrub and should be removed.

‘Red Majestic’ is a new contorted filbert. The new spring growth emerges with burgundy red tint which bleaches out to a dark green foliage by late May.

Powis Castle Artemisia Is Exceptional

Posted by Hugh on March 16th, 2012

'Powis Castle' Artemisia

Most artemisias (aka “wormwood”) can not cope with the summer heat and humidity in the mid-South. Their silvery foliage tends to burn out (some say “melt out”) in mid to late summer. ‘Powis Castle’ artemisia is truly the exception. Powis Castle is likely a hybrid (Artemisia arborescens x A. absinthium

Powis Castle is a bushy, woody-based perennial or subshrub which forms a 2-3 foot high and wide mound. Powis Castle rarely flowers. Its finely divided foliage is evergreen in most gardens in the Southern Appalachian region (USDA hardiness zones 6 and 7). The silvery foliage creates an excellent contrast with green and other colorful leafy plants in the garden.

Artemisias are best planted in well drained soil and in full sun. They tend to grow poorly in soggy winter soils. No soil fertilizing is generally necessary. Diseases and insect problems are of little consequence.

Older plants tend to run randomly because of their rhizomatous root system. Do not cutback artemisias in the fall. Instead, treat them as hardy mums or asters and wait until new spring growth appears before pruning back. Tidy up the garden bed to recapture a fresh new foliage look.

Its aromatic foliage is cut and utilized in creating fresh herbal wreaths and in potpourri. During medieval times wormwood was a popular remedy for whatever ailed you from gout, kidney stones, scurvy and liver problems.

‘Goshiki’ Osmanthus Brightens Up Any Garden Spot

Posted by Hugh on March 13th, 2012

Holly-like foliage of 'Goshiki' Osmanthus

Holly Tea Olive (Osmanthus spp.) comprises a number of evergreen shrubs from Japan which are winter hardy in USDA zone 7- 9. ‘Goshiki’ (O. heterophyllus ‘Goshiki’) is a hardier compact evergreen shrub, which grows very slowly at 3-4 inches per year. It is long-lived, maturing to 5- 6 feet in height and 5 to 7 feet in width after many years.

The Japanese name “Goshiki” translates to “five colors”. Its spiny juvenile foliage mimics American holly (Ilex opaca). New leaves start out with a rosy pink tint, shortly becoming pale yellow and gold flecked over a dark green background. Tiny white flowers in late October are mostly inconspicuous, hidden within the leaf axils. Flower fragrance is very pleasant from several feet away. Tiny bluish black fruit are rarely seen in most years.

Goshiki prefers a moist, well drained and acidic soil. It grows in almost any garden spot from full sun to light shade. Utilize Goshiki in a low front or medium border, a low screen, and a short hedge. Its spiny foliage forms a sharp barrier deterrent.

Goshiki is winter hardy in the Southern Appalachian region (USDA Zones 6 and 7). Osmanthus is mostly pest-free and deer resistant.

Efforts To Solve Japanese Barberry Invasive Problem

Posted by Hugh on March 11th, 2012

'Crimson Pygmy' Japanese Barberry

Japanese barberry (Berberis thunbergii) is a very popular landscape shrub. Japanese barberry is indigenous to Eastern Europe and Asia and is commonly planted in USDA hardiness zones 4-8.

There is justified concern over the invasive nature of Japanese barberry. A number of states have declared most barberry species (Berberis spp.) to be invasive and have banned its future use. Invasive plants may displace and overtake native species, thereby reducing biological diversity. Native fauna populations, which depend on native species for food and shelter, also suffer.

Cultivar selections are very numerous. Shrub sizes may vary from 5 to 8 feet in height and 6 to 9 feet in spread. Foliage colors range from green, yellow, gold, purple, red and variegated types. Dark yellow flowers bloom in early spring, and many set few to large crops of small bright red berries which may persist into the winter.

Japanese barberry thrives in full sun and in any soil that is well-drained. It tolerates urban air pollution, moderate shade, and drought. Japanese barberry is effective as a living fence or hedge in yards and parking areas. It also makes a thorny deterrent against deer.

Current research on Japanese barberry centers on evaluating the seed viability of current cultivars and to breed new sterile (seedless) cultivars. ‘Aurea Nana’, ‘Aurea’, ‘Bagatelle’, ‘Golden Devine’, and Mentor barberry (B. x mentorensis) have a low seed count. ‘Aurea Nana’, ‘Aurea’, and ‘Golden Devine’ sport vibrant yellow leaves, while Bagatelle has red leaves and Mentor has green leaves.

All About Crabgrass

Posted by Hugh on March 8th, 2012

Young crabgrass seedling

Crabgrass is an annual grassy weed which dies out around the first autumn frost. Seeds dropped last summer germinate when the soil warms up from early spring through summer. When spring soil temperatures reach 55-60 degrees (the forsythia shrub is blooming), apply a pre-emergent crabgrass preventative. These herbicides are very effective applied in late winter and again in early July in the Southern Appalachian region (USDA zones 6 and 7).

Some additional lawn care tips to reduce crabgrass infestations:

1.) Spring lawn fertilizing. A thick lawn keeps out crabgrass by making it harder for the crabgrass seeds to sprout. Split apply a slow release lawn fertilizer in late winter and again in mid-spring at the equivalent rate of 2 lbs of actual nitrogen per 1000 sq. ft.

2.) Mow high. A thick, tall lawn grass keeps the soil temperatures cooler and prevents sunlight from lighting the soil. Short mowing weakens the grass, and warms up the soil, making crabgrass seed easy to germinate. Seeds don’t germinate well over shaded ground.

3.) Delay lawn renovation (reseeding bare spots) until fall. In the spring lawn seed germinates in a few weeks, but crabgrass seed comes up faster. Fall seeding is better because crabgrass is dying and new lawn seeding germinates and grows rapidly without crabgrass competition.

4.) Dethatch and aerify lawns in early fall. Crabgrass loves compacted soils. Soil aerification, if needed, is best delayed until fall because you are opening the ground, favoring crabgrass seed germination.

5.) Lime, if needed, in the late fall. Lime raises the soil pH. The proper soil pH allows more nutrient uptake to the lawn grass which means a healthier growing turf.

Outdoor Greenery for Interior Winter Decoration

Posted by Hugh on March 5th, 2012

If you are a new property or home owner, perhaps you’re planning some landscaping this year. Likely, you have several objectives in mind. You might include a few evergreen and deciduous shrubs and trees which, in later years, can be cut for holiday wreaths, garlands, swags and indoor ornamentation. Here is a short list to consider:

American holly (Ilex opaca) — yellow-fruited cultivar pictured)

Winterberry holly (Ilex verticillata)

Canadian hemlock (Tsuga canadensis)

Southern magnolia (Magnolia grandiflora)

Annabelle hydrangea (Hydrangea arborescens ‘Annabelle’)

Limelight hydrangea (Hydrangea paniculata ‘Limelight’)

Boxwood (Buxus spp.)- select from many great cultivars

Summersweet shrub (Clethra alnifolia)

Harry Lauder’s Walking Stick’, contorted filbert (Corylus avellana ‘Contorta’)

Pussy willow (Salix discolor)

There are several other hollies from China and Korea that may substitute. While hydrangea and clethra are not evergreens, the dried spent blooms are very decorative in holiday arrangements. The twisted branches of ‘Harry Lauder’s Walking Stick’ filbert or the furry buds of pussy willow adds any table floral decor over the late fall and winter seasons.

Redbuds With Very Few Messy Seed Pods

Posted by Hugh on February 27th, 2012

Ugly Seed Pods on Redbud (C. canadensis)

A few years back my church pastor complained about the ugly load of seed pods covering the redbud branches (Cercis canadensis) on the property in the fall. My suggestion to avoid messy seed pods is to plant seedless redbud cultivars.

A number of native redbud (C. canadensis) cultivars produce few to no seed pods. Let’s start with the cultivars ‘Ace of Hearts’ and sister seedling ‘Little Woody’ which may set fewer than a dozen per tree per year. ‘Hearts of Gold’ (with chartreuse foliage) often sets low pod numbers one year and produces heavy amounts the next. ‘Forest Pansy’ (with dark purple foliage) sets a small scattering of pods annually.

‘Merlot’ is a new glossy wine red foliage redbud from the North Carolina State Redbud Breeding program, and it produces few pods. The pods which form after flowering rarely set viable seeds and the pods abort early. ‘Flame’ is a rare double flowering form, most of which are sterile and the tree sets very few pods.

‘Don Egolf’ Chinese redbud (C. chinensis ‘Don Egolf’) is female sterile and develops no seed pods.

‘Traveller’ (C. texensis) is a weeping redbud hardy to Zone 6 and its flowers are sterile and podless. “I have seen only one pod on ‘Traveller’ in 20 years”, says Dr. Dennis Werner, NCSU Ornamental Plant Breeder.

Parrotia: A Great Medium-sized Landscape Tree

Posted by Hugh on February 16th, 2012

Persian ironwood mottled bark

Parrotia (Parrotia persica), aka “Persian ironwood”, is native to Iran, Turkey, and the Caucasus region. Parrotia forms a lovely carefree medium sized lawn or street tree. Tree framework is vase-shaped, initially narrow at the base and flaring out in the canopy as it ages. Mature tree height varies 25-40 feet, depending on location and the seedling or cultivar planted. Rated hardy in USDA hardiness zone 5, parrotia excels in the Southern Appalachian region (USDA zones 6 and 7).

Tiny flowers appear in early March and are rarely noticed along its branches. Clusters of ruby red stamens emerge with no petals. In early spring its witchhazel-like foliage starts out reddish-purple and develop into 3-5 inch long leaves. Summer’s lustrous dark green foliage transitions to a blend of yellow, orange and red colors in autumn. Foliage colors are effective for almost a month.

After 12 – 15 years parrotia’s smooth gray bark begins to exfoliate. In subsequent year, a patchwork of green, white, tan and cinnamon unfolds. Prune away lower branches to better catch the striking mosaic bark.

Parrotia is long-lived with no serious insect or disease issues. A two-year established parrotia resists heat, drought, wind, and urban air pollutants. Seasonal leaf colors are more vivid in full to partial (6 hours minimum) sunlight and on a well-drained acidic soil site.

‘Biltmore’ is most popular cultivar which exhibits tall and upright branching. ‘Pendula’ is a spreading weeping mound form only 10-12 feet wide with branch tips which tend to curve upward.

Within the witchhazel family (Hamamelidaceae), besides parrotia and witchhazel (Hamamelis spp.), are such landscape favorites as sweetgum (Liquidambar spp.), fothergilla (Fothergilla spp.) and loropetalum (Loropetalum chinense).

Key Points Whether To Grow Peaches

Posted by Hugh on February 6th, 2012

Select The Best Peaches for Your Region

Peaches grow in other places besides Georgia, USA. A decade long period of mild winters in the Southern Appalachian region (USDA zones 6 and 7) have increased gardener confidence about growing peaches. Peaches (Prunus persica) tend to flower in early spring when the threat of spring frosts is still high. In many years spring frost may kill 80% of flower buds, yet still produce a “full” crop in July and August.

Standard (non-dwarf) peach trees grow and are easy to harvest by pruning them to 10-12 feet in height. Dwarf peach trees are unreliable as they live only a short time and are not worth the high purchase price. Dwarf peach root systems are weak and break off from the graft union.

Only freestone peach varieties are listed below. If you garden in zone 7-a or further north, their long winter chilling requirement is not a problem. Freestone peaches are great for eating and ideal for baking and canning; the flesh does not stick to the pits. Clingstone peaches are also a good choice for their sweetness and taste.

Table 1. New peach varieties and approximate harvest times for East Tennessee, Western NC and Southwest VA (zone 6-b):

3^rd week July Contender (yellow flesh, freestone)

4^th week July Nectar (white flesh, freestone)

1^st week August Carolina Gold (yellow flesh, freestone)

2^nd week August China Pearl (white flesh, freestone)

Late August Intrepid (yellow flesh, freestone)

Table 2. Older reliable varieties for East Tennessee and Southwest Virginia include:

Cresthaven (medium to large fruit, yellow flesh, freestone)

Jefferson (early season, medium yellow-orange flesh, freestone)

Monroe (late harvest, medium yellow flesh, freestone)

Red Haven (medium, nearly fuzzless, yellow flesh, freestone)

Credit: Dr. David Lockwood, Extension Fruit Specialist at the Universities of Tennessee and Georgia recommend these varieties.

Don’t Crawl /Let’em Weep White Pine

Posted by Hugh on January 15th, 2012

4-foot Young Weeping White Pine

Pinus strobus 'Pendula'

In the beginning was a small weeping pine which wanted to crawl along the ground because it had no “legs”. The gardener came along and straightened up the leader and attached it to a tall pole. Straightening and staking continued for several years. Many years later it grew into a tall weeping white pine (Pinus strobus ‘Pendula’).

The leader and branch shoots pf white pine emerge in late April. The 3 – 5 inch long needles have fully elongated by early June in the Southern Appalachian region (USDA zones 6 and 7). Staking is best performed anytime from mid to late June. The shoots become semi-woody, yet are still flexible.

The main shoot (leader) is bent vertically upward and tied to the stake. The staking and tying procedure is neither complicated nor time consuming. Use soft jute or cotton twine, and not wire twist-ems® or plastic ties for fastening to the stake or a trellis. After 6-8 months, loosen the ties so they won’t girdle the tender main shoot (leader).

At planting position a sturdy 12-16 foot metal or heavy duty plastic stake close to the trunk. White pine grows 12-18 inches per year. On rare occasions a tree may produce multiple leaders. Remove all but the one you want to continue up the stake. Within 8-10 years, your weeping white pine should support itself on its strong straight leader and the stake may be permanently removed.