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

‘Kintoki’ Japanese Cornel Is Perfect Fit for Small Urban Gardens

Posted by Hugh on February 27th, 2011

: ‘Kintoki’ summer foliage

It’s a dogwood and comes close to being a plant that offers four seasons of landsape beauty. Kintoki Japanese cornel (Cornus officinalis ‘Kintoki’) is a special semi-dwarf 10-12 foot tall dogwood which fits into most small gardens. Kintoki’s bright yellow flowers open in early March in the Southern Appalachian region (USDA zones 6 and 7).

Bloom season is almost 4- weeks long, and begins 3 – 4 weeks ahead of forsythia. A frigid winter’s evening does not hurt the blooms. The foliage exhibits a dark green polished finish and purplish fall foliage color does not occur is not until late November.

Japanese cornel grows in most soils as long as the drainage is good. Plant in a full sun to partial shade location where it’s easily visible from inside your home. When in bloom, March weather is often wild and changeable and gardeners can remain warmly huddled indoors.

In the fall attractive Kintoki’s multi-colored bark and bright edible drupe fruits offer autumn thru winter interest for humans, birds and other wildlife. Over the next 2-3 years, availability of Kintoki is likely to be limited to specialty nurseries selling in the internet marketplace.

Revitalize Pansies Now

Posted by Hugh on February 18th, 2011

Across many areas of the Southern Appalachian region (USDA zones 6 and 7) snowfall has been plentiful this winter, but total rainfall is below normal. It takes 10 inches of snow to equal one inch of rainfall.

Fall planted pansies and violas are now both hungry and thirsty. Provide them with a shot of fertilizer and water. Winter feeding will not injure these hardy plants.

Apply an agricultural grade of fertilizer such as 19-19-19 or equivalent. Do not use a slow release granular product this time of year as the fertilizer prills do not release their nutrient charge in cold soils. Any water soluble fertilizer, including Miracle Gro® or Jacks® brands, are also good choices for feeding pansies and violas. Follow package directions.

Irrigate thoroughly after feeding to wash the nutrients into the soil as well as to re-hydrate plants. Watering also prevents the fertilizer salts from burning the plant foliage.

Withis a few days your listless pansies should perk up during this warm weather spell which we are currently enjoying.

The Other Lenten Roses

Posted by Hugh on February 7th, 2011

Lovely cut foliage of Bearsclaw hellebore

In addition to the popular Oriental hellebore (H. x orientalis), four other species are hardy in the Southern Appalachian region (USDA hardiness zones 6 and 7). Christmas rose (H. niger) is the first lenten rose to bloom, often 4-6 weeks earlier if mild December weather permits. The 3 ½- inch flowers are large and showy, each borne singularly on 2 to 2 ½ foot tall stems.

Corsican hellebore (H. argutifolius) features large yellowish green flowers and glossy light green leathery foliage. Leaves are holly-like, with spiny deeply cut edges. Flower longevity lasts 10 or more weeks. The slightly nodding flower heads emerge from the crown to stand above the foliage. After the seeds ripen in mid-summer, stalks collapse to make room for new growth. Corsican hellebore may require some winter protection in coldest locales of the Southern Appalachian region.

Bearsfoot hellebore (H. foetidus) flaunts dark green, deeply dissected foliage. Each of the green blossoms is edged in purple and blooms at same time as H x orientalis. This species is best planted in a cool, shaded garden area as it is not heat tolerant.

Hellebore blooms make long lasting additions to any cut flower arrangement. To prevent the leaves, buds and flowers from wilting, re-cut each stem using a sharp knife or bypass pruners while holding the stalk submerged in water. This practice assists in continuous water uptake in the stem and improves flower longevity.

Lenten Roses Perk Up the February Garden

Posted by Hugh on February 2nd, 2011

Helleborus x hybridus

Lenten roses or hellebores (Helleborus spp.) are long-lived perennials, often surviving in the same garden spot for many years. Four species of Lenten roses grow in the Southern Appalachian region (USDA hardiness zones 6 and 7). All thrive in shady garden recesses, exposed to as little as 3 – 4 hours of dappled sunlight. Numerous new cultivars have been introduced over the past 25 years.

Foliage is coarsely tooth, palmately compound, the leaflets arranged like fingers on a hand. Lenten roses bloom from mid-February through April and are available in white, pink, green, plum or reddish-purple.

Lenten roses love a loamy well drained soil rich in organic matter or compost. A limey soil pH around 7.0 or slightly higher is best. Mulching around plant(s) contributes to their garden longevity. Hellebores are drought tolerance, but regular watering during dry summer periods is encouraged.

Plants should be divided every 4-5 years either in the early spring, soon after flowering, or in early fall. Wear when handling seeds or plants as the sap may cause skin blisters. Lenten roses are highly poisonous to most animals, including humans, and are quite resistant to deer and vole feeding.

Most popular is the Oriental hellebore (H. x orientalis, often written H. x hybridus). They offer the most color choices of any species. Flowers average 3-inches in width and heads are slightly nodding. Flowers are borne on single stems and petals are often spotted or flecked.

Next Blog: The Other Lenten Roses

Two Sensational New Oakleaf Hydrangeas

Posted by Hugh on January 24th, 2011

'Ruby Slippers' oakleaf hydrangea

Oakleaf hydrangea (Hydrangea quercifolia) is a popular native shrub in the Southeastern U.S. (USDA hardiness zones 5 to 8). Two new compact forms of oakleaf hydrangea were recently introduced by the U.S. National Arboretum.

In early summer, ‘Ruby Slippers’ is covered with 9-inch-long floral clusters that are held upright above the foliage. ‘Ruby Slippers’ grows to about 3 ½ feet tall and 5 feet wide and has large creamy white flower panicles that mature to a deep rose color in late summer. ‘Munchkin’ is slightly smaller at 3 feet tall and 4 ½ feet wide, and 6 ½ inch long white flowers age to a medium pink color. Both cultivars grow in either light shade or full sun.

Their compact form and dense plant habit make it ideally suited for use in small residential landscapes. The new light green foliage in spring turns dark green in summer and mahogany-red in fall. Both are ideal specimen shrubs planted either individually or together as a lovely deciduous hedge row.

‘Ruby Slippers’ and ‘Munchkin’ were developed by Dr. Sandra Reed, plant breeder at the U.S. National Arboretum Research Lab, located at the Tennessee State University Nursery Research Center in McMinnville, TN.

2012 Perennial Plant of the Year Named

Posted by Hugh on January 21st, 2011

Brunnera 'Jack Frost'

The Perennial Plant Association (PPA) has selected Brunnera macrophylla ‘Jack Frost’ as the 2012 Perennial Plant of the Year. Runnersup for 2012 honors were Panicum virgatum ’Northwind’, Heuchera ‘Caramel’ and Chelone lyonii ‘Hot Lips’.

Brunnera ‘Jack Frost’ foliage is deer resistant. It grows to a height and width of 12-15 inches. Its silvery foliage stands out in a shade garden. Brunneras produce racemes of blue star-like flowers in mid to late spring.

Grow ‘Jack Frost’ brunnera in a compost-rich, well-drained soil. Water plants regularly during summer dry spells. Mulching around plants also benefits.

Brunnera inhabits the shade garden alongside other favorites such as hostas (Hosta spp.), lungworts (Pulmonaria spp.), coralbells (Heuchera spp.) and variegated Solomon Seal (Polygonatum odoratum ‘Variegatum’).

Brunnera ‘Jack Frost’ was commercially introduced in 2000 by Walters Gardens in Zeeland, Michigan.

Reminder: The 2011 Perennial Plant of the Year is Arkansas Bluestar (Amsonia hubrichtii)

Stop the Leyland Madness

Posted by Hugh on January 18th, 2011

Leylands Gone Wild!

Leyland cypress (x Cupressocyparis leylandii) is a tall, fast growing evergreen tree or shrub. Many are planted as privacy screens. Ask yourself, should you really plant a 50 foot barrier between you and your neighbor(s)?

In the Southern Appalachian region (USDA hardiness zones 6 and 7), there are shorter and better evergreen choices. In the 12-16 foot category:

Boxwood (Buxus spp. and hybrids)

Plum yew (Cephalotaxus harringtonia) ‘Fastigiata’

Hinoki cypress (Chamaecyparis obtusa)

Japanese falsecypress (Chamaecyparis pisifera)

Dwarf Burford holly (Ilex cornuta ‘Dwarf Burford’)- clipped

Inkberry (Ilex glabra)

Foster holly (Ilex x attenuata)- clipped

American holly (Ilex opaca)- clipped

Nellie R. Stevens holly (Ilex x ‘Nellie R. Stevens’)- clipped

Skip laurel (Prunus laurocerasus ‘Schipkaensis’)

Yew (Taxus spp.)- upright or fastigiate forms

Eastern arborvitae (Thuja occidentalis)

Leatherleaf viburnum (Viburnum rhytidophyllum)

Prague viburnum (Viburnum x pragense)

Leyland cypress is susceptible to three serious canker diseases, in which pruning is the principal curative remedy. Leyland is also susceptible to bagworms. Their enormous growing height makes pesticide spraying and pruning options almost impractable and costly.

From the start, don’t plant leylands closer than 12 feet apart (recommend 16 feet spacing). Plants will touch within 4 years after planting. During the first three summers, young leylands require deep watering as they’re not drought tolerant. A 2-3 inch mulching depth in the row aids in conserving soil moisture.

Hardy Dwarf Deodara Cedars

Posted by Hugh on January 13th, 2011

'Glacier Blue' Deodara Cedar

Over the past ten years, deodara cedar (Cedrus deodara) has carved its niche into Southern Appalachian gardens (USDA zones 6 and 7). Three zone 6 hardy dwarf cultivars, ‘Glacier Blue’, ‘Devinely Blue’, and ‘Feelin Blue’, fit today’s smaller garden space better than most tree forms of deodara cedar that typically reach 70-80 feet in height. All three sport lovely soft blue-green foliage.

Deodara grows best in full sun to light shade in moist fertile, well-drained soil. Deodara needs good air movement to prevent problems with needle diseases. New deodaras require regular watering during summer dry spells. All three cultivars make great accent plants among large boulders, other dwarf conifers, and rockery plants.

‘Glacier Blue’ grows 5-8 feet tall in ten years. Growth rate is moderate with a spreading to slightly pendulous arching form.

‘Devinely Blue’ grows only 3-6 inches annually. It matures into a 6 feet tall and 3 feet wide shrub. New spring foliage starts out gray-green and turns bluish green.

‘Feelin Blue’ exhibits a prostrate growth form similar to ground cover junipers. At maturity it reaches 3-4 feet in height and 6-8 feet in spread.

Winter Care of House Plants

Posted by Hugh on January 10th, 2011

: Lovely Foliage Plants at Grove Park Inn in Asheville, NC

Most plants adapt to winter’s shorter daylength and low light intensity. Interior plants require less water and nutrients. Plants also adapt to the lower room humidity in our modern day homes. Grouping plants together and spritzing them 1-2 times a day is helpful.

Soil moisture needs varies with the type of plants and the kind of containers (plastic, clay or ceramic). How long has the plant been in the same pot or planter? Plastic and ceramic pots retain soil moisture longer than clay pots.

I urge gardeners to adopt a simplistic house plant care approach. Fit plants on your everyday schedule. Make watering part of the Saturday morning chores or after Sunday church services or prior to Sunday game kickoff. Water 1-2 times weekly. If some plants don’t need water, skip them.

As winter wanes, tackle the job of re-potting those plants that have not been re-potted in one year. Gently shake off some old potting mix and transplant into a slightly larger container and new soil-less media.

Beginning March 1st, feed plants every 2-3 weeks. Most branded “house plant” fertilizers work well. My personal tip is to decrease recommended label amounts by half, and fertilizie plants twice as often from March through October.

Be vigilant about bugs and diseases. Simply washing the foliage with a mild dish washing soap, insecticidal soap or miscible oils can clean off most pest problems. Frequently, pest problems can be resolved without using inorganic pesticides.

Hardy Camellias — start with this one!

Posted by Hugh on January 4th, 2011

Occasionally, gardeners need abit of confidence before purchasing a plant considered not winter hardy where they live. Twenty years ago, growing a camellia was a folly inside the Southern Appalachian region (USDA zones 6 and 7), until the Drs. Ackerman and Parks’ introductions appeared. These hardy cultivars have changed the playing field.

Recently, I asked some local camellia “experts” what one favorite cultivar gardeners should start with. While none wanted to go on record as picking just one, ‘Pink Icicle’ (pictured) appeared on everyone’s long list. One landscaper stated that he planted ‘Pink Icicle’ in an open full sun garden area of a cemetary ten years ago and all have prospered.

‘Pink Icicle’ blooms nearly two months in March and April from New York, NY, southward and westward to St. Louis, MO. It sports a glossy dark green foliage which is better looking than most fall blooming cultivars. Choose a garden location where the camellia is protected from mid-afternoon summer sun and blustery winter winds.

The culture of camellias is similar to rhododendrons and azaleas. A camellia established for two or more years in its garden space exhibits above average drought tolerance.