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

Too Early Fall Color A Telltale Signal Of Tree In Trouble

Posted by Hugh on October 6th, 2013

'Red Sunset' Maples Coloring In Late September in Tennessee (photo by Ken Soergel)

Early leaf color or premature leaf drop often tells a property owner that their tree(s) may not be healthy. Photo above, taken in front of a new subdivision, says alot. Large red maples show leaf color weeks ahead of their natural timeline. Notice the narrow median where the trees are planted.

The cause of early foliage change may be weather-related, a foliar or root disease, an earlier insect infestation, or a site with one or more environmental factors. Extremes of either a dry or a wet summer (flooding) may lead to premature leaf drop or early fall leaf color. Urban air pollutants can be blamed.

In this landscape situation (photo), red maples were the wrong tree choice for the site. Red maple is nicknamed “swamp maple”; you find the species naturally growing along streams, and near lakes and ponds. Red maple has a notoriously shallow root system, a network of surface roots that destroy a home lawn or lift sidewalks.

In this example, on an obvious dry soil site, crape myrtle (Lagerstroemia spp.), sweetgum (Liquidambar styraciflua), elms (Ulmus spp.), Chanticleer pear (Pyrus calleryana), hornbeams (Carpinus spp.), or yellowwood (Cladrastis kentukea) would have been better tree choices.

A professional landscaper should have known that the tree choice was wrong. Unfortunately, mistakes like this are all too common.

Paperbark Maple Offers 4- Seasons Landscape Interest

Posted by Hugh on October 4th, 2013

In the winter some gardeners get excited about tree bark, particularly if you own a paperbark maple (Acer griseum). This small 25-30 foot tall tree has an upright spreading branching habit. The cinnamon-colored bark flakes off naturally in thin strips or chips. Horticulturists call this “exfoliating”. The sturdy branches are not prone to breakage in stormy weather.

Fall leaf color is variable. The foliage of select cultivars and some seedling forma turn scarlet red. The dark green trifoliate leaves present a fine texture to a summer garden. Spring flowers are mostly inconspicuous. Two winged samara fruits (many call them “helicopters”) start dropping in early fall. Most seeds do not germinate and create a weedy mess.

Plant in full sun in northerly hardiness zones 5 and 6, and protect from the direct afternoon summer sun in southerly zone 7. Paperbark maple prospers in moist, well-drained, compost-rich, and moderately acidic soil, but does adapt to average soil that are adequately drained. Water a newly planted tree regularly over the first two years until fully established. Paperbark maple is generally slow growing, often less than 12 inches a year.

Paperbark maple provides shelter for birds and other wildlife. It has no serious disease and pest problems when properly sited. Its slow growing nature rarely asks for pruning. Maintain a year-round mulch that’s 2 to 3 inches deep to maintain adequate soil moisture.

Location, Location, Location. Truly, it is in the fall and winter seasons when paperbark maple shines. Set paperbark maple where its exquisite trunk’s bark is on show all winter long. Consider landscape lighting as the tree ages and becomes grander.

Most paperbark maples in the marketplace are seedling forms, and may vary widely in bark color. Two noted cultivars include:
• Gingerbread® (‘Ginzam’) with darker cinnamon-red bark and orange-red fall color;
• ‘Cinnamon Flake’( A. griseum and A. maximowiczianum) features darker green summer foliage and exfoliating bark of tiny chips.

‘Halloween Hocus Pocus’ Daylily For Garden Goblins

Posted by Hugh on October 1st, 2013

'Halloween Hocus Pocus' daylily

On a pleasant July morning I saw my first ‘Halloween Hocus Pocus’ daylily (Hemerocallus x ‘Hocus Pocus’) in a friend’s garden. The 5 ½ inch flowers stand on 26 inch tall stems (scapes) and the foliage is semi-evergreen.

The cultivar name describes it best. Its creamy orange color with a triangular black throat and wide blacken edged petals are the perfect colors of Halloween. Flower throat is small and yellow green. Floral form is very round and full with petals overlapped. Petal substance is thick and smooth, and holds up well to full sun.

Flowers are borne on well-branched scapes and carry multiple blooms. Hocus Pocus is a vigorous grower and a mid-season bloomer. If properly watered and not subject to summer drought stress, it should re-bloom dependably in the late September into early October.

Flowers are similar to another Salter 2006 introduction ‘Halloween Trick’ which has plum color rather than blacken edges. In some catalogs it may also be listed as ‘Hocus Pocus’ and is classed as a tetraploid.

DOs and DON’Ts Checklist Before Purchasing Plants

Posted by Hugh on September 29th, 2013

Root Inspection of Japanese Maple

When shopping at the garden center don’t bring home problem plants. “Plants On Sale” should raise a caution flag. Thoroughly inspect all sale plants. They may have been sitting many months with the pots now full of weeds, diseases, or pest problems. They become tightly potbound and roots will need to be teased apart prior to planting. Some of my worse garden weeds got their start from a purchased plant. Nutsedge and oxalis are two of worse to bring home.

Inspect the underside of leaves for bugs. If the pots are easy to lift weight-wise, pop the pot off and look for live roots. Root rot diseases like Photophtora and Pythium can seriously kill roots of holly, rhododendron, azaleas, junipers in containers.

Not all roots are white-colored, but should appear plump and moist. The potting soil (media) should not contain dry patches. The media has lost its ability to hold water (“hydrophobic”). If you’re purchasing 10 or more plants, inspect 2 to 3 items.

Once home, isolate all suspicious plants for 1-2 weeks prior to planting. Recent warnings about boxwood blight should raise your concern. Boxwood blight is primarily spread from newly purchased boxwoods that introduce the disease to an existing planting. Daylily rust is started in much the same matter. It is carried from new daylily purchases.

One final point! Some percentage of plant roots growing in black nursery containers may be dead. The side of the pot facing the sun (outside rows) is where to inspect. Black containers absorb excessive solar heat, usually on the west-facing side, and roots frequently die. When purchasing plants, select plants from inside and not on the edge of the block. Similarly, winter cold temperatures may kill roots on the exposed sides of overwintering containers.

Tropical Flowering Maple

Posted by Hugh on September 26th, 2013

Chinese Parasol Tree Is Colorful Tropical

(Abutilon spp.), often called Chinese lantern or Chinese parasol plant, is a tropical houseplant (USDA hardiness zones 8-10). It offers pendant umbrella-shaped flowers along with handsome rich green five-lobed maple-like foliage. Some variegated leaf forms are available. Leaf petioles are long.

Utilize as a tropical foliage plant in the garden or a container. The brightly colored flowers are stunning. A pot plant often blooms earlier than one planted in the ground. The blooms attract hummingbirds and other pollinating insects. Some varieties are slightly cold hardier (zone 7-b), but this is no guarantee. The over-wintered plant outdoors seems to take most of the summer to struggle back and re-bloom.

Many hybrid varieties originate from Asia, Africa, and South America. Flowering may occurs in all four seasons, indoors as well as out. High light and warm temperatures of summer are mostly to their liking. For optimum growth and bloom, flowering maple needs high light from a south or east facing window and 68-72 °F minimum room temperatures.

Repot in April or May before moving outdoors in the garden. Move back indoors when night temps drop below 40 °F. Flowering maple grows exceptionally fast to 6 – 8 feet in height from spring to fall.

Follow a weekly watering schedule to establish a deep, extensive root system. Feed with a water-soluble fertilizer such as Miracle-Gro™, Jack’s™ or Daniels™ monthly at half the package rate during the spring, summer and fall months. Feed sparingly over the winter.

Prune twice annually in early spring and mid-summer to control plant size and shape. If the plant gets too leggy indoors, clip it back hard to increase branching. Flowering maple is frequently plagued by pesky whiteflies. Inspect your plant(s) for bugs before bringing indoors in the fall.

Flowering maple is easily propagated from cuttings and from seeds. Some plants may live 10 years and older and develop a 3 to 4 inch wide trunk.

Why Some Crapemyrtles Do Not Flower

Posted by Hugh on September 23rd, 2013

Sparse Flowering Caused By Multiple Factors

There are several probable reasons why your crape myrtle did not flower this summer. The two leading reasons are lack of adequate daily sunlight and planting depth. Crape myrtles should be planted in full sun. They don’t flower well in locations receiving less than 6 hours of direct sunlight each day.

If the leaves are being heavily attacked by aphids or fungal diseases like Cercospora leaf spot and powdery mildew, the plant is not producing enough carbohydrates (food) to initiate flower buds. Also, the aphids feeding may be inflicting damage to the flower buds.

“Crape Murder” pruning after new spring growth has started can delay or completely eliminate flowering. Overpruning often promotes excessive growth at the expense of flowering. In fact, crape myrtles require little annual pruning. In most years pruning on crape myrtles should be mostly cosmetic, such as to cut off a dead or crossing branch or to remove last year’s old seed heads.

Poorly drained (too wet) soils is another cause. Unusually heavy amounts of rain may retard or completely eliminate flowering. Crape myrtles must be planted on a well-drained site. Heavy rainfalls also leach nutrients out of the ground.

Over-applying nitrogen-based fertilizers may push your crape myrtle into vegetative growth and few, if any, flowers may develop.

Crape myrtles do not tolerate deep planting. The upper-most (surface) roots should be at ground-level or an inch or two above, never several inches below the soil line. When planted too deep, the roots don’t get enough oxygen, leading to reduced growth and flowering.

Crapemyrtles can recover from deep planting over several years. They must regenerate a new root system closer to the surface. Removing mulch piled up around the base of the plant will help roots breathe.

Special Thanks to: Dr. Gary Knox at North Florida Research Center

Beautyberry Deservedly Becoming More Popular

Posted by Hugh on September 20th, 2013

Vibrant Purple Berries of American Beautyberry

The stunning purple berries of beautyberry (Callicarpa spp.) are eye-catching in late summer. White fruited varieties are also sold, but the purple forms are most popular. This 6-8 foot shrub has medium green, 3-5 inch long foliage spring thru summer. Autumn leaf color adds little, the deciduous leaves turning purple to pale yellow, shriveling, and abcising.

The purple fruit clusters are electifying, perhaps nature at its gaudiest. Individual fruits measure 1/4 inch or less in size, and clustered together around the stems, creating quite a show. Numerous species of birds feed on the fruits, either from the Japanese (C. dichotima) and native (C. americana) forms.

Clusters of pink or lavender colored flowers open in mid-July, and are mostly unnoticed because of their small size; flowers are somewhat hidden within the thick foliage.

Grow beautyberry so the magnificent late summer fruit display may be easily seen. Beautyberry thrives in full sun to partial shade (as little as 1 hour of sunlight needed). Its soil needs are average, although beautyberry grows and fruits best under full day sun and in moist well drained soils. Mulch plants to reduce weeds and to conserve soil moisture.

Prune to remove winter injured branches (in USDA zone 5) and to open this dense growing shrub to additional sunlight. Heavier pruning may be required to control its wild-like nature further south. All pruning should be completed by mid-spring. Flowers and fruits form on new season’s growth.

Viable seeds are dispersed into your landscape and your neighbors’ yards as well. Invasiveness is currently unproven , so plant the native species just in case. The foliage is rarely troubled by disease or pest problems.

Better Blackberry Varieties Available

Posted by Hugh on September 18th, 2013

Trellised blackberries beginning to fruit

Growing Blackberries

Blackberries (Rubus spp.) are among the easiest fruit crops to grow in the Southern Appalachian region (USDA hardiness zones 5 and 7), but are not as hardy as raspberries.

A blackberry planting has a productive life between 8-10 years. A sturdy trellis system, composed of strong posts and wire, will make harvest chores easier. You can expect a partial crop the second year after planting and full crops in year three and beyond. Blackberry culture is similar for raspberries.

Select and prepare the planting site. Blackberries prefer open full sun and grow best in well-drained, sandy loam soils rich in organic matter. Avoid low ground areas which suffer from poor air and soil drainage. An available water supply is necessary for maximum berry yields and size.

Soil preparation is most important for multi-year harvests. Test your soil to determine its pH and fertility levels. Blackberries prefer a acidic soil pH range between 5.6 to 6.2. Most county Extension offices offer soil testing services for a small fee.

Based on your soil report, add generous amounts of organic matter and well-rotted manure to garden soil. Unless your soil analysis states differently, broadcast 20 to 25 pounds of 10-10-10 fertilizer per 1,000 square feet over the planting area.

Blackberries require good field sanitation which includes annual cane pruning. They have few disease and pest problems. Weeds will be a common problem as they attract potentially serious pests. Mulching helps reduce weed infestations and conserve soil moisture.

Select virus-free, high yielding, and great tasting varieties. Blackberry Varieties* (by order of ripening):

Thorned:

Choctaw –small berry, high yields
Chickasaw –large berries
Kiowa –very large berries
Shawnee –high yields

Thornless Erect:

Natchez –large berries
Arapaho –low yields
Ouachita –high sugar levels
Navaho –firm berries
Apache –large berries, white drupelets

Thornless Semi-erect:

Chester –very high yields, late ripening
Triple Crown

* Blackberry varieties recommended by Dr. David Lockwood, Fruit Specialist with the Universities of Tennessee and Georgia

‘Guacamole’ Hosta An Outstanding Garden Performer

Posted by Hugh on September 14th, 2013

'Guacamole' Hosta Flowers in August Garden

Guacamole (Hosta plantaginea ‘Guacamole’) is rated one of the top performing hostas in the Northeast and mid-South U.S. gardens. Guacamole is a hybrid and one of its parents is H. plantaginea ‘Fragrant Bouquet’. In 2002 it was selected Hosta of the Year by the American Hosta Society.

Guacamole is a medium-sized hosta. It matches its catalog description within three years. Guacamole grows 1 ½ feet tall and three or more feet wide with a mound-like habit. New spring leaves unfurl with apple green centers and dark bluish-green margins. Summer foliage darkens to avocado centers and medium green margins. The high gloss leaves average 10 inches in length and 8 inches in width. Leaf venation is moderate at best.

In August multiple scapes of white funnel-shaped flowers rise 36 inches tall above avocado green foliage. Yes, the flowers are fragrant, but their scent is never overwhelming.

Hostas prefer a moist, compost-rich, well-drained soil. They are the most popular shade perennial, yet many handle full sun well under regular irrigation. In northerly areas (USDA hardiness zones 4-5) with cooler summer, most hardy cultivars grow in full sun. While mostly free of diseases and pests, many cultivars are susceptible to foliar damage from slugs and snails. Deer are also a serious menace.

Hostas should be divided every 5 years, either early spring or mid-autumn. In early spring wait for shoots to poke up, but before leaves unfurl. As leaves decline in the fall, dig up the entire clump and divide with a sharp knife.

Guacamole was introduced by Solberg in 1994.

Aster ‘Raydon’s Favorite’ Is Spectacular Autumn Bloomer

Posted by Hugh on September 11th, 2013

Aster 'Raydon's Favorite' in late October

Aster Raydon’s Favorite (Symphyotrichum oblongifolium ‘Raydon’s Favorite’) is one of our most reliable native perennial asters. This aromatic aster blooms in mid-autumn, covered with 1 ½ inch wide blue-purple daisy-like flowers with yellow centers.

Butterflies and bumble bees are frequent visitors to this aster in my October garden. Night temps in the mid-twenties don’t injure the flowers. Leaves and stems emit a minty, aromatic aroma when crushed. Raydon’s Favorite also is an excellent cutflower (U.S. hardiness zones 3 to 8).

Raydon’s Favorite forms a compact mounding shrub, growing 3 to 4 feet tall after 2-3 years, slightly wider than high. To produce more flowers and improve plant density and uniformity, prune this aster back by half in mid-July and allow it to re-grow. Feed plants again with a water-soluble fertilizer such as Miracle-Gro®, Jack’s® or Schultz® according to package directions.

Grow in full sun and in average garden soil; it flourishes in a compost – rich soil. Established plants are exceptionally drought tolerance. Feed at planting time or in early spring with a slow-release fertilizer such as Osmocote®. After flowering is completed, cut back and gather up branches to reduce seed dispersal into other parts of the garden.

Asters need to be divided once every 3 to 4 years to keep them growing vigorously. Raydon’s Favorite appears to be disease or pest free. Plant(s) should be divided in either spring or fall or from cuttings taken in early summer.

Raydon’s Favorite began appearing in garden centers about 1995, introduced by Allen Bush from a plant he received from Raydon Alexander in San Antonio, TX, from a plant he acquired on Lookout Mountain in Tennessee.