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

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.

Urban Trees Reap Cleaner Air

Posted by Hugh on January 30th, 2014

Urban Tree Planting In Downtown Charlotte, NC

U.S. Forest Service scientists with the Center for Urban Forest Research report that planting and nurturing street trees in Indianapolis, IN returned 500 percent in benefits from storm water reduction, energy conservation, cleaner air and increased property values.

The researchers evaluated more than 117,000 trees the city’s Parks and Recreation Forestry Section manages. It found that every $1 spent brought a $6.09 return. Each tree annually removed 1.5 pounds of air pollutants, valued at $2 per tree or $212,000.

“Indianapolis’ urban forest is uniquely diverse, with only one of over 170 species representing slightly more than 10 percent of the total tree population,” said Greg McPherson, Center for Urban Forest Research director. Species diversity is important because the urban forest is at less risk of catastrophic losses from diseases or pests.”

Scientists found Indianapolis trees annually intercept 318.9 million gallons of rainfall, an estimated worth $1.98 million or $17 per tree per year. Trees also annually cut electricity use by more than 6,447 megawatt hours, worth $432,000. They reduce natural gas use by more than 150,000 therms, yielding annual benefits of $165,000 or $5 per tree.

Total annual tree benefits varied by species and size. For example, silver maples (Acer saccharinum), representing the largest species planted, produced the greatest benefit at $60 per tree, but they also were the most expensive to manage. Several were nearing the end of their productive lives and required removal or intensive care.

Source: U.S. Forest Service, Center for Urban Forest Research, January 2014.

Winter Sap Bleeding From Trees Not Harmful

Posted by Hugh on January 28th, 2014

Icicle Off Poor Pruning Cut in Fall

Winter can be a cruel period for trees. Day-night temperatures may wildly fluctuate and drying winds tend to injure tender buds. Maples (Acer spp.), flowering dogwoods (Cornus florida), birches (Betula spp.), yellowwoods (Cladrastis kentukea), walnuts (Juglans spp.) and elms (Ulmus spp.) are “bleeders”. The sap pressure inside branches is highest during the winter months.

If any tree jeopardizes a house, property, utility lines, and human safety, it should be pruned no matter the time of year. The bleeding sap phenomena is over-rated. Winter-pruned bleeder trees will not die. If it humanly bothers you, prune these “bleeder” species in the summer when sap pressure is lowest.

Leaky sap may drip on pedestrians, cars, and walkways resulting in stains on trunk bark and sidewalks. Puddles on walkways may freeze and create slippery pavement.

Bleeding or sap loss will eventually stop on its own. Quickly, the pruning wound cuts have internally sealed off and the healing process started.

Spraying paint (wound dressing) does not help. Many times the sap flow is so plentiful as to wash the wound paint off. You may want to irrigate the tree during dry spells to speed wound healing.

If you’re seeking advice about pruning large shade trees, consult a certified arborist first. The International Society of Arboriculture (ISA) website should list one or more in your area.

Soil Sampling Is Good Insurance

Posted by Hugh on January 25th, 2014

Soil sampling is good gardening insurance!

Do you know what your soil needs to grow a great lawn, flower, or vegetable garden? If you haven’t analyzed the soil in the past five years, get it done in any season. Most gardeners do it in late winter when university, state, and private soil labs are busiest.

The local Extension office or a garden center can supply you with one or more sample kits with instructions and forms detailing how to sample. Mail the soil, form, and money to the soil lab.

If soil conditions have drastically changed because great amounts of organic matter, topsoil, etc. were added or accidentally spilled fertilizer or another chemical, retest your soil. Do you have a special problem area? Separately test this spot and explain the problem. Photos are optional.

In early fall, before you’re ready to tackle a major fescue/bluegrass lawn renovation, soil test before the work starts. Be sure to mark on the form that you want recommendations for a lawn. With a lab results in hand, they detail how many pounds of fertilizer to apply. If lime or sulfur to raise or lower the soil pH, that is included on your report.

If you’re planting acid-loving plants such as azaleas, blueberries or mountain laurels (Kalmia app.), inform the soil lab; they will estimate when and how much sulfur to apply. Planning a home fruit orchard (apples, peaches, plums, grapes, brambles), tell the lab intended use of the land.

Basic sampling instructions: using a trowel, take 8-10 random samples of topsoil from various parts of your yard. Dig only 5-6 inches deep. Mix all together thoroughly in a bucket. Place a small amount of the soil mixture in a paper (not plastic) bag or box, enough to fill a small baby food jar. Do not ship wet soil.

“Death By Mower” Disease

Posted by Hugh on January 22nd, 2014

Dead Dogwood By “Mower Disease”

“Mower disease” is a totally preventable human malady caused by permitting lawn grasses and weeds from growing near the crown of trees and shrubs. The problem is commonly seen on large properties such as church grounds, cemeteries and public parks. Large gang mowing machines (with many reels) cut 95-98% of the turf area. Workers follow along with push mowers and string, blade weed-eaters or “weed wackers” around trees and shrubs.

String mowers are blamed for most of the unsightly bark injuries. The tree or shrub is eventually weakened by sap leakage and nutrient loss. The damage also exposes the tree/shrub crown to numerous disease infection and insect borers.

A better management practice is to maintain a thin organic mulch zone around the tree or shrub base. The mulch should never be piled up against the trunk. A mulch layer more than 4 inches is not recommended.

Weeds will eventually grow on surface of decaying mulch barrier. Periodically, hoe or hand-pull invading grasses and weeds atop the mulch. An alternative is to spray a weed herbicide such as Round-up™ or an equivalent product according to label directions. When done, add 1-inch of mulch for a fresh clean appearance.

Nativars – New Cultivars Of Native Plants

Posted by Hugh on January 20th, 2014

Improved Serviceberry Nativar ‘Autumn Brilliance’

Nativar is a new term coined by Dr. Allan Armitage, Professor Emeritus from the University of Georgia. It combines the words “native” and “cultivar”. Nativar refers to a cultivar of a native plant. It attempts to excite the horticultural marketplace about new cultivars of native perennial plants, such as blackeyed Susan (Rudbeckia spp.), purple coneflower (Echinacea purpurea), coreopsis (Coreopsis spp.), and many others.

Nativars are native plants that resulted from natural or man-made cross pollination. Many natives have undergone a so-called “facelift”, one that enhances the plant’s appeal or improves past deficiencies such as better flowers or disease resistance. The “new and improved” versions drive new sales of natives to professional landscapers and gardeners. This excites their pop and sizzle at the garden center.

A native tree may not develop good fall color. When an individual plant is spotted in a nursery row or in a forest, the nativar is born, tested, named, and propagated. Plant scientists at the University of Tennessee found anthracnose resistant flowering dogwood (Cornus florida) in a Maryland forest. It was tested, propagated, and named ‘Appalachian Spring’. Since its introduction sales of native dogwoods have increased.

A single nativar may be derived from a large seedling population which possesses wide genetic variability for its ecological surroundings. The nativar may not excel over thousands of acres. For example, a nativar exhibiting deep red fall color may not express this color trait a thousand miles away.

Provenance, where the plant originates, plays an important role. Red maples (Acer rubrum) grow in a wide geographical area in the U.S. and Canada. A cold hardy red maple from Wisconsin will likely not survive a hot humid Georgia summer; a Georgian red maple may not cope with a hard Wisconsin winter. An Oregon red maple nativar with flashy red fall color may fizzle in the southeastern U.S.

Native aster species (Symphyotrichum spp.) grow over a wide geographic area of the eastern U.S. Not all aster nativars planted on a single site will flourish.

Baptisia ‘Purple Smoke’ is hybrid nativar of two species

European Hornbeams Serve As Great Garden Sentinels

Posted by Hugh on January 17th, 2014

Touch of Fall Color on Carpinus betulus 'Columnaris'

Upright European hornbeams (Carpinus betulus cvs.) are versatile small to medium-sized deciduous trees that fit most landscape settings. Depending on which cultivar you select, the tree stands with a narrow vertical profile. It grows 35-40 feet tall and 15-20 feet wide. It’s cookie cutter by design as a street tree or tall narrow hedge.

Hornbeams are best planted in late winter balled and burlapped (B&B) and in any month if container-grown. Tall popular cultivars ‘Fastigiata’ and ‘Columnaris’ are being supplanted by shorter growing ‘Frans Fontaine’.

Leaves are small, dark glossy green on the surface and finely serrated along the edge. Autumn foliage turns golden yellow. Tiny spring flowers and pendulous clusters of samara seeds are ornamentally insignificant. European hornbeam is often nicknamed “muscle wood” or “ironwood” as its smooth gray main trunk is muscular.

Annual growth rate is slow. Hornbeams are long-lived when properly sited and nurtured. They prefer in moist, well-drained, acidic to slightly alkaline pH soil. Full open sunlight or partial 5 to 6 hours of sunlight is adequate. Newly planted trees should be irrigated every 7 to 10 days over the first two summers if summers are unusually dry. Otherwise, hornbeams are moderately drought tolerance. Fertilize young trees in late winter with granular 10-10-10 or equivalent. Pruning is rarely needed except to maintain the narrow upright form.

Young trees may be fashioned into a tall hedge or screen, set out 5 to 10 feet apart. Create a garden arch by planting two rows 8-10 feet apart; bend and attach tree tops (leaders) over time to form a natural archway or hut.

Are Your African Violets Looking OK?

Posted by Hugh on January 14th, 2014

Sickly African violet plant

Healthy African violet plant

African violets (Saintpaulia ionantha) are easy to grow flowering house plants. Modern day varieties sold at supermarkets and plant shops often bloom 8-9 months a year.

Lighting needs are minimal, either from indirect sunlight from an east-facing window or under special “grow lights” 12 hours daily. African violets prefer water at room temperature (65-75 °F). Fill your watering container several days prior to watering to evaporate off fluorides and chlorides in the water.

Common problems with African violets are overwatering and fertilizer scheduling. Feed violets twice monthly, November thru February, with any brand “house plant” fertilizer. Use 1/2 the amount recommended on the package added to water. From March thru October, feed 3-4 times monthly with 1/2 rate solution. You must feed plants without burning roots with fertilizer salts. Once each month leach pots thoroughly, watering pots from above. Repot all plants once a year, generally in early autumn.

Water all plants at same time and never leave pots standing in water more than 1 hour. For old or large plants, a second watering may be occasionally needed as the roots fill the pot and need more. In general, interval between waterings may be 5-6 days. Waterlogged plants are an indicator of poor roots or bug infestations.

Check for mealy bugs. They often start out looking like debris (dust or soil) over the leaf surfaces and petioles. A mealy bug outbreak can build quickly. Applying rubbing alcohol to individual bugs with a cotton swab every 3-4 days should clean up an infestation within a month. Insecticidal soap, applied every 3-4 days, is also effective.