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

Volcano Mulching Harmful

Posted by Hugh on January 1st, 2012

Mulch Piled Up Around Tree

Piling up mulch around trees or shrubs, called “volcano mulching”, is a bad practice and is killing them. Perhaps you’ve seen a neighbor or a professional landscaper doing it, and assumed that it must be alright. It’s not!

The deep mulch pile smothers the natural buttress flair of the trunk which breathes and absorbs air for the rootsystem. The sugary sap underneath the thin bark skin is a food source for harmful insects which overwinter in the mulch piled around the bark. It also becomes a haven for critters, particularly rabbits and field mice.

Organic-based mulches aid to conserve soil moisture, moderate soil temperature extremes and reduce competition from weeds. It also keeps mowers and string weeders (“weed wackers”) away from potentially damaging the tree trunk.

Mulch depth is recommended at 2-3 inches and is distributed around the tree in the form of a donut. The bulk of the mulch should lay 3 or more inches away from the trunk and taper off near the tree’s dripline (outer extent of branches). Excessive depth of the mulch also promotes shallow rooting by reducing oxygen to the roots. Trees become more susceptible to prolonged periods of drought.

Organic mulches include pine bark, hardwood bark, chopped leaves, pine needles, and composted grass clippings.

Grow And Re-bloom Christmas Cactus

Posted by Hugh on December 28th, 2011

Thanksgiving cactus

Holiday cacti, aka Thanksgiving cactus (Schlumbergera truncata) and Christmas cactus (S. x buckleyi ), are popular houseplants which grow (and re-bloom)for many years with good care. Christmas cactus has rounded (scalloped) stem segments while Thanksgiving cactus has 2-4 pointed teeth paired along each segment edge. The latter blooms 3-4 weeks earlier than Christmas cactus and is available in several colors. Holiday cacti are actually tropical epiphytes (like orchids) and not true cacti.

Holiday cacti bloom when exposed daily to uninterrupted 12-hour dark periods over 6-8 weeks starting in late September. A dark closet is a good place to do this. They also bloom when exposed to cool temperatures between 50 to 55 °F regardless of dark exposures.

Flower buds may drop prematurely due any of four factors: 1. over-watering, 2. low room humidity, 3. dry potting soil, and 4. insufficient light. Do not place a plant near a cold or warm draft such as a heating vent or poorly insulated window in your home.

Holiday cacti produce more blooms under bright light. Site your plants in a sunny window indoors, or beneath a shade tree in the summer garden. Leaf edges may redden or burn when exposed to excessive light.

When blooming in the fall and early winter holiday cacti are kept moderately dry and not fertilized. Water and fertilize in spring and summer when actively growing with houseplant-type fertilizer such as Miracle-Gro™, Peters®, Hollytone® or Schultz®. Follow the label directions. In March or early April holiday cacti are to encourage better branching before new spring growth begins.

Before the start of spring, repot the plant into a slightly larger container containing a well-drained sterile houseplant potting mix.

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Foster Holly Has It All

Posted by Hugh on December 25th, 2011

Bountiful Fruit Crop on Foster Holly

Foster holly (Ilex x attenuata) is an old holly favorite which has not lost its sizzle. While many new holly cultivars have entered the landscape scene, do not assume that Foster holly is now passé. It is utilized in a number of landscape options in the Southern Appalachian region (USDA zones 6 and 7), including in containers in zones 7 and 8.

Originally, there were five selections of Foster holly introduced by E. E. Foster of Foster Nursery, Bessemer, AL in the 1940’s. Still the most popular today is ‘Foster #2’, a female clone which produces a bounty of small bright red holly berries. Fruits continue to be effective throughout the winter. ‘Foster #4’ is its male pollinator mate, but in most locales, male American hollies (Ilex opaca) will also pollinate Foster #2.

Holly (Ilex spp.) grows in a moderately acidic (pH 5.8 – 6.5), well-drained soil and in full to partial sunlight. Feed with a water-soluble acidic fertilizer such as Miracle –Gro™, Miracid™, or Hollytone®.

Foster hollies display a strong vertical accent when utilized as specimen or foundation shrubs in front of tall buildings or on the corners of residences. They form a 12–20-foot dense evergreen privacy screen and may be sheared as hedges. Tall overgrown Foster hollies may be cutback severely in early spring for a small compact size. Heavy clipping can transform them into almost any topiary shape that you desire.

New Poinsettia Varieties Make Your Holidays Bright

Posted by Hugh on December 23rd, 2011

'Shimmer Surprise'

'Miro' poinsettia

Poinsettia is a gift which keeps on giving. Many gardeners save and nurture their plant to re-bloom again over the next winter holiday season. By early February the plant has likely dropped most of its bottom leaves and flower bracts. Cut back the bare stems by two-thirds and don’t be concerned about the oozing white sap. Care for the poinsettia as a house plant (watering and fertilizing) and provide light from a home window with eastern or southern exposure.

In mid to late March repot into a container, 1 – 1 ½ times larger. Move the plant outdoors on warm spring days when temps are above 50°F and back indoors on cool nights. The plant will spend most of the spring and all summer outdoors where it will easily double or triple in size with a regular watering and fertilizing. Cutback the shoot tips once or twice during the summer to increase branching.

In early fall, your poinsettia moves back indoors on cool evenings (below 50°F) and kept isolated in a room which is not lighted in the evening hours. Poinsettia requires 6 weeks of uninterrupted 12- hour nights to initiate flowers and colorful bracts. The plant receives adequate light during the daytime hours and watering and feeding continues.

By mid-November, small flower buds form and the upper leaves (bracts) begin to color up and increase in size. By the next winter holiday season your poinsettia will decorate your home once again.

'Winter Rose' poinsettia

Prickly Pear Is Easy Care

Posted by Hugh on December 17th, 2011

Prickly pear cactus (Opuntia)

There are over 200 species of prickly pear cactus (Opuntia spp.) worldwide. Several make great container plants in the garden or inside the home. Prickly pear cacti may grow to heights of 10 feet or more in the arid regions of the Southwestern U.S.

Eastern prickly pear (Opuntia compressa var. ‘humifusa’) grows 12- 18 inches tall and 30-36 inches wide. It will grow a bit larger in a warm moist habitat. The reddish “pear” fruits ripen in the fall. They taste like kiwi fruits and can be made into jam and jelly. The 3-4 inch wide bright yellow cactus flowers bloom in early summer in the Southern Appalachian region (USDA zones 6 and 7).

Prickly pears need a well-drained soil, preferably sandy or gravely, and they’re planted in full sun. Irrigation and fertilizing are rarely needed. Overwatering causes pads to collapse and the root system to rot. Cacti plants may appear wilted after a cold winter, but perk up and become fully turgid by early spring.

They are easily propagated from pad sections directly into the garden or a container. Allow the cut end to air dry (heal over) for 5-7 days before setting, cut end down, to a 2-inch depth into garden or potting soil. Moisten the soil after planting and no further watering is needed. Pad(s) generally root in 4-6 weeks.

Prickly pear spines greet you with hostility. Wear thick heavy duty gloves to protect yourself from the large smooth spines and small, hair-like needle spines over the pads.

Trifoliate Orange –The Barbed Wire of the Plant World

Posted by Hugh on December 12th, 2011

Winter View of Trifoliate Orange

Trifoliate orange (Poncirus trifoliata) is a hardy citrus native to China. T-orange is hardy to -15° F. This strong growing large shrub or small tree can reach 15 to 20 feet in height. Its foliage is deciduous and compound, compared to citrus trees with single simple evergreen leaves.

T-orange prefers full day or partial (minimum of 6 hours) sunlight. After one year establishment, it can cope with moderate periods of drought. T-orange grows in a soil pH range between 6.2 to 7.5 in average well-drained soils. One 3-4 oz. annual application of 10-10-10 granular fertilizer per plant in late winter provides adequate nutrition.

Showy 1 ½ to 2 inch white, mildly fragrant flowers open from late April into early May in the Southern Appalachian region (USDA zones 6 and 7). Golf ball sized green fruits turn rusty yellow (not orange) in late summer and are quite aromatic. The bitter fruits are edible and loaded with seeds.

Numerous heavy- duty, 1-2 inch long spines (thorns) form along deep green stems. The dominant spines seem to attract plant buyers to this “Little Shop of Horrors”. Plant it as a hedge to deter trespassers, if that is something you need to do. Aggressive pruning or shearing shapes and limits its size, but be advised to wear thick protective gloves and pack some extra band-aids.

T-orange is used as a winter hardy rootstock in commercial citrus groves. Some concern has been raised of its potential invasiveness.

‘Flying Dragon’ is a dwarf form with stems and thorns contorted or twisted. It grows well in pot culture.

Key Points About Growing Peaches

Posted by Hugh on December 8th, 2011

Flowering peach in Early Spring Garden

People think peaches grow only in Georgia. A decade long period of mild winters in the Southern Appalachian region (USDA zones 6 and 7) have increased gardener confidence in growing peaches. Peaches (Prunus persica) tend to flower in early spring, when the threat of spring frost is high across the region. In many years spring frost may kill 80% of their flower buds, but still manage to produce a full crop in July or August.

Standard peach trees grow and are easily maintained through pruning at 10-12 feet in height. Do not plant dwarf peach trees as they live only a short time and are not worth their cost. Dwarf root systems for peaches are weak and break off from the graft union within a few years.

Select only cold hardy, great tasting peach varieties. The finest freestone peach varieties with long winter chilling requirement are listed below. If you garden in zone 7-a or further north, these are suited for your area. Freestone peaches are great for eating, baking and canning; the flesh does not stick to the pits. Clingstone peaches are also sweet and tasty.

Table 1. New peach varieties and approximate harvest times in East Tennessee 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, recommends these varieties.

Disease Free Apple Varieties

Posted by Hugh on December 6th, 2011

Apple Selection at Local Supermarket

Over the past 30 years, the goal has been to develop good eating and storing apples which are not susceptible to four major diseases. The first 3 cultivars released were ‘Prima’, ‘Priscilla’, and ‘Sir Prize’, but they lacked great flavor and storage quality.

Apples are susceptible to four serious diseases: apple scab, cedar-apple rust, fireblight, and powdery mildew. Scab, rust and mildew foliar diseases required a rigorous fungicide spray routine every 7-10 days from spring petal fall up to harvest. Fireblight is a bacterial disease without any satisfactory control measures other than pruning off dead twigs and branches.

Gardeners are looking for better non-pesticide (organic) options. Here are 5 “no-spray” disease resistant varieties:

‘Liberty’ – McIntosh type flavor with good to moderate resistance to all 4 diseases.

‘Freedom’ – crispy, slightly tart red medium to large fruit for both eating, cooking and juice; 3 month storage life.

‘Goldrush’ – crispy, nearly ‘Golden Delicious’ in flavor, slightly tart; good keeping quality; susceptible to cedar apple rust.

‘Enterprise’ – new sprite tasting red skin/white flesh variety with good keeping quality after harvest.

‘Arkansas Black’ – old timey variety with good disease resistance; tart apple whose flavor improves after 1 month in storage; long keeping time; skin color turns almost black.

The development of disease resistant cultivars has greatly diminished the number of fungicide sprays required to grow a successful crop. Insect control is still needed.

Credit: Dr. David Lockwood, University of Tennessee Fruit Specialist suggested these 5 disease resistant varieties.

Everbearer Raspberries Harvest from July To Frost

Posted by Hugh on December 5th, 2011

: Raspberry Production at Biltmore Estate, Asheville, NC

Everbearer raspberries are easier to grow compared to the June-bearer types. Everbearer types are often called “fall bearers” because they produce berries from very late July to late September. Pruning becomes a simple chore – in late winter simply cut down all canes (shoots) to the ground. The traditional June crop is lost, but the new spring canes produce a large summer- fall crop.

Fall bearers grow best in full sun and in well-drained soil. Raspberries prefer a soil pH of 5.6 to 6.2. Drip irrigation over the summer months is needed to keep plants stress-free during incessant summer heat and drought periods. Mulching also aids in weed prevention and retaining soil moisture. In March and May apply one pound of 10-10-10 garden fertilizer per 100 square feet of bed. Do not fertilize in summer.

For backyard fruit enthusiasts grow raspberries on raised beds. Construct a sturdy trellis for cane support during the summer. This keeps most of the fruit off the ground and easier to pick. Trellis should be strongly built to handle the heavy yields starting in the 3^rd season. The canes will bend down the support wires.

‘Caroline’, ‘Nantahala’, ‘Autumn Britten’, ‘Fall Red’ and ‘Heritage’ are reliable red everbearer varieties. ‘Anne’ and ‘Fall Gold’ are golden tinted red everbearer berries. Fall bearing raspberries are easily available from on-line e-commerce nurseries. Purchase only rooted canes which are certified disease-free.

A patch of raspberries provides many years of healthy and luscious fruits, high in fiber and loaded with minerals, vitamins, anti-oxidants, and anti-carcinogens.

European vs Asian Pears

Posted by Hugh on December 4th, 2011

Luscious European Pears

Growing pears in the Southeastern U.S. is both challenging and rewarding. Both the European (Pyrus communis) and Asian (P. pyrifera) pears are susceptible to fireblight (Erwinia amylovora), a bacterial disease with no satisfactory cure. Two popular European pear varieties, ‘Bartlett’ and ‘Bosc’, are highly susceptible to fireblight. Varieties found to be fire blight resistant are: ‘Warren’, ‘Aires’, and ‘Moonglow’. ‘Shinto’ is an Asian pear variety with crispy russet brown fruits and possesses above average fireblight resistance.

European pears are unique in that the fruits do not ripen on the tree. Fruits must be harvested on a scheduled date for each variety and ripened indoors. The unripened pears are stored in a closed plastic or paper bag (sack) for 7-10 days at room temperature (60-70 °F). Fruits are then refrigerated to slow down ripening.

Asian pears ripen on the tree like apples, and are ready to eat when harvested. Asian pears are picked from late August to early October, depending on the variety grown.

European pear varieties will not pollinate Asian pears. Asian pears tend to bloom several days later than European varieties. Both European and Asian pears also require cross-pollination of two different varieties.

Both European and Asian pears are notorious for “biennial bearing”. A tree may overproduce one year, and yield a small crop the next (the ‘off” year). Biennial bearing in the “on” year often results in limb breakage and smaller fruits. To prevent or break the biennial bearing cycle, remove excess fruits by hand within 30 days after full bloom in the “on” year. As a rule, one pear fruit is supported by 30-40 leaves.

Volcano Mulching Harmful

Grow And Re-bloom Christmas Cactus

Foster Holly Has It All

New Poinsettia Varieties Make Your Holidays Bright

Prickly Pear Is Easy Care

Trifoliate Orange –The Barbed Wire of the Plant World

Key Points About Growing Peaches

Disease Free Apple Varieties

Everbearer Raspberries Harvest from July To Frost

European vs Asian Pears

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