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

Early Spring Flowering Okame Cherry

Posted by Hugh on March 3rd, 2014

Mid- March Flowering Okame Cherry

‘Okame’ Cherry is a hybrid between Taiwan Cherry (Prunus campanulata) and Fuji Cherry (P. incisa) (USDA hardiness zones 6-8). Okame is the first ornamental cherry to bloom in the Southern Appalachian Region (USDA hardiness zones 6 and 7).

In the midst of a mild winter, Okame often starts blooming a few days after Valentine’s Day (February 14). Most years their lovely fuchsia pink flowers appear in mid-March and survive overnight temperatures in the upper twenties °F.

Following petal fall the dark red calyxes stay on for another 2-3 weeks. In early summer dark red ovoid drupe fruits ripen and are consumed by numerous species of birds.

Spring leaves start out bronze tinted and turn dark green and glossy through spring and summer. Foliage turn bronze-red before dropping in mid-autumn. Okame’s polished reddish-brown bark is marked with gray horizontal lines called “lenticels”.

Okame matures into a small tree, 20 to 30 feet in height and 10 to 15 feet wide. The tree’s upright branch form makes it an ideal candidate as a street tree. Don’t neglect summer watering its first two years after planting.

Okame is best planted in well-drained loamy soil and in open full sun. The tree tolerates light shade, but blooms heaviest in full sun. As a rule, ornamental cherries are susceptible to several diseases and pests, but Okame cherry is more resistant than most. In early summer inspect tree(s) for Japanese beetles, scale and spider mites and treat accordingly. Prune annually to remove dead, diseased or pest ridden branches, if any. Good air movement around tree also helps.

‘First Lady’ and ‘Dream Catcher’ are 2003 and 1999 U.S. National Arboretum releases respectively. Both are rated as improved hybrid forms of Okame cherry. Both cultivars typically grow 20-30 feet tall with upright branching. Branch tips are weep slightly, and are blanketed with single, dark rose-pink flowers in late March to early April.

Sweetbox – Excellent Evergreen Shrub For Shady Areas

Posted by Hugh on February 28th, 2014

Late Winter View of Sweetbox

Few evergreen shrubs grow in the shade. Sweetbox (Sarcococca hookeriana var. humilis) is a compact dwarf evergreen shrub or ground cover which is easy to grow (USDA hardiness zone 5-b to 8). Foliage remains lustrous dark green year-round.

Sweetbox grows in partial to full shade, 1 to 2 feet tall and 6 to 8 feet in spread. Fragrant white flowers appear in mid-to late winter which your nose may sense before your eyes. Blue-black berry-like fruits ripen in fall and winter and are quickly consumed by birds.

Sweetbox grows best in mildly acidic, well-drained, compost-rich soil. If two or more, space plants 5-6 feet apart. Feed with a 6-month rated slow-release fertilizer yearly or fertilize with a water-soluble fertilizer for acid-loving plants. Irrigate during the summer months when weekly rainfall amounts are infrequent. Two-year established plants exhibit good drought tolerance.

Sweetbox, a member of the boxwood family (Buxaceae), provides a dark green backdrop for spring-flowering bulbs and shade-loving perennials. It forms a long-lived ground cover beneath deciduous trees. Its evergreen foliage is utilized in making fall-winter wreaths and other holiday displays.

Rake tree debris, e.g. twigs and leaves, away from the planting to keep sweetbox looking neat. Disease and pest problems are rare. Foliage is resistant to many air pollutants. Scale may occasionally become a serious pest.

Sweetbox is rarely sold at local garden centers, but is easily purchased on-line. Because sweetbox is slow-growing, it does cost a bit more, but is a worthwhile long-term investment.

Challenging Sourwood Worth A Try

Posted by Hugh on February 25th, 2014

Beautiful July Flowering Sourwood Tree

Sourwood (Oxydendrum arboreum), aka lily of the valley tree, is one of the most beautiful U.S. native flowering trees (USDA hardiness zones 5-9). However, attempting to establish one in your landscape may prove challenging.

The tree grows in sparse populations from eastern Tennessee, western North Carolina, and Georgia Piedmont. It grows naturally to 20-30 feet tall shrub and 35-40 feet tall tree. Most trees grow in a narrow pyramidal form, less than 15 to 20 feet wide.

Sourwood offers four seasons of landscape beauty. Delicate-looking white fragrant flowers (racemes) open in early July and may bloom 3 to 4 weeks. The pendulous 10 to 16 inch long creamy bell-shaped floral sprays drape from the growing tips of branches. The seed capsules turn gray in late fall and persist through the winter.

Sourwood‘s spectacular fall leaf color is an array of burgundy, scarlet, and purple lasting over 2 to 3 weeks. Its deeply fissured bark is similar to persimmon, and easier to view after autumnal leaf drop.

Sourwood prefers well-drained acidic soil and sited in full or partial sunlight. A tree in heavy shade does not bloom as well or provide a spectacular fall foliage as one in mostly full sunlight.

Few cultivars are available. Reasons to nurture a sourwood tree in your landscape: July flowering time, lily of the valley floral sprays, awesome red fall color, major winter food source (seed) for birds and wildlife, and delicious sourwood honey. Flowers attract numerous bees and butterflies.

See also blog titled: “Tips For Growing Sourwood”

Tips On Growing Sourwood Trees

Posted by Hugh on February 22nd, 2014

Awesome Fall Color Of Sourwood In Western North Carolina

Sourwood (Oxydendrum arboreum) is one of the most beautiful flowering trees in the U.S. Trying to establish one in your landscape can prove quite challenging. In the wild sourwood grows in shallow soils on steep craggy or rocky ground. Dry ground seems to be the rule. It grows either multi-stemmed (shrub-like) to 20-30 feet or tree form to 35-40 feet and half that in width.

Sourwood is a pioneering species. Tiny dehiscent seeds are dispersed into the wind and blown like dust over many acres of land. Tens of thousands of seedlings germinate each spring on new ground that may have been previously clear cut for reclamation. If available, supply water intermittently over dry periods the first two summers. Established trees tend to better cope with heat and dry soils.

For a home gardener the challenge seems to be getting one established. Site them in the type of soil and environmental conditions which rhododendrons and mountain laurels enjoy. They prefer a loose, gravelly, acidic soil containing some organic matter and excellent drainage. A newly-planted sourwood prioritizes by establishing its root system first.

Purchase primarily nursery container-grown trees, if you can find them. Plant in well-drained soil and prune the new tree or shrub back to 6-12 inches from the ground in early spring. Essentially, you are starting over with 100% root system and 10-15% top (shoot). What comes up is your new tree, more vigorous than one not pruned.

In nature sourwood seem to prefer the eastern facing slope of the woodland where they receive midday sun. Young transplants respond to fertilizing; older well-established trees do not. Sourwood requires little pruning and has few serious insect or disease problems.

Prune to Rejuvenate Old Foundation Shrubs

Posted by Hugh on February 18th, 2014

Old fashion Nandina in Desperate Need of Pruning

Eventually, old foundation shrubs around your home grow too tall and spindly and need to be started over. Rather than digging them up, most deciduous and a few broadleaf shrubs respond to rejuvenation pruning. Sorry, evergreen conifers do not respond to this form of pruning.

Get started with a sharp pair of pruning loppers or tree saw for the large cuts and hand pruners for smaller cuts. February and March are good times to rejuvenate old shrubs.

Before getting started with pruning, understand what you’re about to do. You desire a low, dense-growing multi-stemmed shrub. Pruning reduces shrub size and redirects new growth from surface roots and above-ground shoots.

Remove the tallest and thickest woody shoots to the ground. Cutback pencil-thick shoots to 12-18 inches from the ground. Remove all weak or dead stems flush to the ground.

After pruning, feed the shrubs, applying 1-2 handfuls of 10-10-10 (or equivalent) granular fertilizer in a 1-2 feet wide circle around each shrub. Disperse no fertilizer closer than 6 inches from the shrub base.

Rejuvenated shrubs should vigorously re-grow in the spring and summer months. Summer flowering shrubs likely will not bloom the first year after pruning.

Caveat: pruned shrubs must be in good health before attempting to rejuvenate them. If they have not re-grown by late May, a trip to the garden center to purchase new plants is in order.

Give Edgeworthia A Try In Your Winter Garden

Posted by Hugh on February 16th, 2014

Paperbush (Edgeworthia) in Bloom in mid-March Garden

To begin, I must thank South Carolina nurseryman, Mr. Ted Stephens, who gifted me a Chinese paperbush (Edgeworthia chrysantha) 12 years ago. Most plant authorities rate its winter hardiness to USDA zones 7 and 8, but no one told this to my edgeworthia in zone 6-b. People who see it blooming in my early March garden like it and ask what it is. While paperbush may struggle its first winter before becoming fully established, it never disappoints.

Paperbush will become a joy waiting for you on a cool March day. Six months later (mid-autumn), its unique nodding floral buds are clearly visible on branch tips. Paperbush is a close botanical relative of the daphnes. Up close, the small tubular flowers are very fragrant!

Flowers are light yellow on the inside and white on the outside. Over the years roots may sucker new plants, eventually developing into a small plant colony. If your plant reaches suckering stage, congratulations, it is happy in your garden.

Paperbush is a multi-stemmed shrub, and new shoots are covered with reddish brown hairs. The 4-5 feet tall and wide plants have attractive greenish blue summer foliage.

Paperbush should be planted in partial shade away from high winds and direct summer sun. Plant in compost-rich, well-drained, acidic soil. Fertilize in early spring with slow-release Hollytone™, Nutricote™, or an equivalent product.

According to Plant Delights Nursery in Raleigh, NC, the species E. chrysantha is more winter-hardy (below 0 °F) than E. papyrifera. Paperbush is a collector’s plant and is sold on-line by e-commerce nurseries.

New cultivars abound including ‘Red Dragon’ with pale reddish-lipped tubular florets and ‘Snow Cream’ with pale yellow florets.

‘Thunderhead’ Pine

Posted by Hugh on February 14th, 2014

‘Thunderhead’ Japanese black pine at UT Gardens, Knoxville, TN

Thunderhead Japanese Black Pine (Pinus thunbergii ‘Thunderhead’) is a dwarf compact form of Japanese black pine (USDA hardiness zones 5b-8). Expect this slow-growing conifer to reach 5 feet high and 4 feet wide in 10 years. Whereas Japanese black pine grows 60 to 80 feet tall, Thunderhead matures to 20 to 25 feet in height and 15-20 feet in spread after many years.

By mid-winter its long silvery buds are clearly visible; they slowly elongate over the winter months. The white candles unfurl in mid-spring. This 2-needle pine has dark green needles which average 3 to 4 inches in length and are densely clustered together.

Japanese black pine grows best in well-drained soil and in full sun. Once established two years, Thunderhead pine exhibits exceptional drought tolerance.

Japanese black pine is a favorite among bonsai enthusiasts and those who sculpt topiaries. In a small garden you’ll enjoy Thunderhead’s natural pyramidal form. No two plants ever look alike if they’re left unpruned.

Japanese black pine thrives along coastal areas with hot dry temperatures and salt spray. Coastal areas of North and South Carolina and Georgia have planted this pine species extensively for sand dune stabilization around beach areas. Along roadsides it stands up to winter de-icing salts.

Hepaticas Bloom In The Early Spring Garden

Posted by Hugh on February 12th, 2014

Hepaticas blooming at Atlanta Botanical Gardens

Hepatica (Hepatica spp), from the Latin word “Hepaticus” meaning liver, is sometimes cataloged as “Liverleaf” or “Liverwort” (USDA hardiness zones 4 – 9). It is one of the first spring wildflowers to bloom (March-April). H. americana, native to the eastern U.S. and Canada, bear showy white flowers that are sometimes tinged pink or blue. H. acutifolia, a Midwest species, features white, pink, lavender, and blue flowered forms. Hepaticas are often purchased from native plant nurseries on-line.

Hepaticas are exceptionally long flowering, long-lived and easy to grow. Individual ½ – 1 inch wide flowers arise before the new foliage unfolds. The anemone-like flowers stand atop hairy 4-8 inch tall stalks. Each flower has 6-10 petal-like sepals subtended by three bracts.

At the start hepaticas tend to grow off slowly. They grow 3 to 6 inches tall in a rich woodsy soil that is well-drained and in a part shade (early morning sunlight) garden spot. In the southern U.S. they grown under heavier shade. Hepaticas thrive in moist and struggle in dry soils. Under optimal growing conditions, vigorous plants will self-seed and form naturalized colonies, each greater than one square foot in area and will bloom prolifically.

The large three rounded lobes (tri-lobed) basal leaves have a dull or matte finish over their upper surface. Late in the summer leaves turn dry and leathery. In southerly climates the old foliage persists all winter and new flowers emerge through the leafy debris.

2014 Plant Winners Announced

Posted by Hugh on February 8th, 2014

Echinacea (coneflower) named 2014 Perennial of the Year by National Gardeners Bureau

Petunia Declared Annual of 2014 by NGB

At the start of each year the Motion Picture Industry awards their Golden Globes and Oscars. The Music Industry has the Grammys. Gardening associations also announce the award-winning plants.

The National Garden Bureau (NGB) has declared 2014 Year of the Echinacea (coneflower) in the perennial category. NGB declared the mighty cucumber as Vegetable of The Year, and Petunia as Annual of The Year. Their primary purpose is to create buzz among gardeners about these great plants. NGB’s website there is lots of reliable cultural information about these plants and other plants. It helps growers and garden centers to increase plant sales.

All American Selections (AAS) trials annuals and vegetables varieties across the United States annually. AAS awards now includes perennials and the 2014 perennial picks are: Gaura Sparkle White (Bedding Plant Award) and Penstemon Arabesque Red F1 (Flower Award).

Perennial Plant Association (PPA) selected Northwind switchgrass (Panicum virgatum ‘Northwind’) as the 2014 Perennial Plant of the Year. This native grass grows 5 to 6 feet tall with a narrow upright form and steel green foliage.

2014 Hosta of the Year (American Hosta Society) – Hosta ‘Abiqua Drinking Gourd’ features deeply cupped, thick textured leaves. The rich blue-green leaves are large size, heavily corrugated.

2013 Stout Silver Medal Winner (American Hemerocallis Society) – ‘Heavenly Angel Ice’ is a re-blooming daylily with 8-inch wide flowers/white petals and green-yellow throat. Flower scapes grow 36 inches high. Note: 2014 winner is designated late in 2014.

2014 Dykes Medal Winner (America Iris Society) – Iris ‘That’s All Folks’ is a tall bearded iris with giant brilliant golden flowers with ruffled and laced edge petals.

2014 Ivy of the Year (American Ivy Society) – Hedera helix ‘Teneriffe’ – an old ivy variety with yellow-cream colored variegated, small-leafed ivy.

Christmas Ferns Are Easy To Grow

Posted by Hugh on February 1st, 2014

Christmas ferns at Cades Cove in the Smoky Mtns, Tennessee

On a woodland hike in the eastern U.S., lush colonies of evergreen Christmas fern (Polystichum acrostichoides) flourish along the moist slopes (USDA hardiness zones 3 to 8). This native perennial fern favors either a deep or light shade environment. A vigorous clump may grow 18 – 24 inches in height and width. Set new plants in a garden 12 – 18 inches apart.

New spring growth has a silvery cast, becoming dark green in summer. The advance of winter gradually takes its toll on the foliage. A gardener may opt to remove the old yellowed or dried fronds in late winter before the new silver green fiddleheads emerge. Fertile fronds have smaller upper leaflets (pinnae) which produce spores on their lower surface.

Christmas fern prefers humus-rich woodland soil with 5.0 – 7.0 pH range. Feeding plants is rarely necessary if the woodland environment is optimum. Decaying mulch around the ferns usually provides adequate nutrition. Fronds stand dark green and tall after a deep soaking summer rain.

As a ground cover Christmas fern tolerates little to no foot traffic. Avoid planting on a poorly drained soil which may lead to crown rot disease.

Whether growing in the wild or in a garden, Christmas fern co-habitats with dozens of woodland plant favorites including celandine poppy, Solomon’s seal, Jack-in-the-pulpit (Arisaema triphyllum), camassia, woodland asters, wild ginger, among others. Its dark green evergreen foliage is utilized for home decorations during the jolly holiday season.