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

Uniquely Different Monkey Puzzle Tree

Posted by Hugh on January 24th, 2018

Monkey Puzzle Tree in Vancouver, BC

Closeup of scale-like foliage

Monkey puzzle tree or Chilian pine (Araucaria araucana) is an evergreen conifer that is native to forested volcanic slopes of the Andes Mountains in Chile and Argentina (USDA Zone 7b-11). It is the national tree of Chile. Monkey puzzle typically grows to 60-70 feet tall and 30-35 feet wide, but may reach heights greater than 100 feet in its native habitat.

It displays a unique loose pyramidal form when young, but develops a rounded canopy along with loss of the lower branches as the tree ages. Horizontal, upward-arching branches are arranged in whorls around the trunk. Bark is gray-brown and ridged.

On the straight trunk, 2-inch long evergreen leaves are glossy, dark green, triangular-shaped, sharp tipped, and closely overlap one another. Individual leaves are leathery and may persist for 10 – 15 years. The horizontal branches are produced in tiers and develop few side branches.

Trees are dioecious (separate male and female trees). The female cones are globular and up to 8 inches in diameter; male cone is cylindrical and up to 5 inches long. Seeds (pinones) are edible and reminiscent of pine nuts.

It is best grown in deep, moderately fertile, evenly moist, well-drained soils and in full sun to part shade. Trees perform well in a variety of different soils as long as sites are well-drained. Trees perform much better in mild summers than in hot climates. In northerly areas, trees may be grown in containers and brought indoors overwinter in bright indirect sunlight.

The tree is rarely troubled by serious insect or disease problems. Needle necrosis and leaf spots. Mealybugs, scales and thrips are occasional pests.

Monkey puzzle is related Norfolk Island pine (A. heterophylla), a popular house plant seen for sale at garden shops during the winter holiday season in the U’S. and Canada.

Winter Honeysuckle Totally Ignored In The landscape

Posted by Hugh on January 21st, 2018

Fragrant honeysuckle in February at Biltmore Estates in Asheville, NC

Glossy brown bark noticeable in winter months

Winter honeysuckle, aka fragrant honeysuckle (Lonicera fragrantissima) is a treasured old-fashioned shrub (USDA hardiness zones 4 to 8). It can still be found growing in older urban neighborhoods and parks. Winter blooming fragrant honeysuckles are a harbinger of spring. Budded branches may be cut and forced indoors.

This vigorous durable shrub grows 6 -10 feet in height and width. Many opt to limb up the lower branches to view the glossy brown wood. Its overall vigor is incredible and gardeners also choose to cut it off at the ground every 5-10 years (after blooming has finished). It is rarely sold in garden centers. Cuttings root easily and you can pass-along this heirloom shrub to gardening friends.

Frequently, here in the mid-South (zones 6 and 7), the small, creamy flowers appear during a warm spell in January – February. It continues to bloom on and off through March. The strong lemony fragrance catches your nose. The spring-summer foliage is blue green and develops little in fall color. Further south (zones 7 and 8), the foliage is almost evergreen.

Fragrant honeysuckle grows in average, dry to medium, well-drained soil, and in full sun to partial shade. Feed with 10-10-10 or equivalent granular fertilizer in early spring. Mulch honeysuckles and other spring blooming shrubs in early spring for weed management and to conserve soil moisture.

While potentially susceptible to a number of disease and pest problems, fragrant honeysuckle is very tough and outgrows most troubles. Pests include aphids, scale, sawfly, whitefly, and webworm. Powdery mildew may show up if summer weather is unusually wet. Hungry bees are especially glad to find any flowering plant in late winter days. The warm sun draw them out in search of nectar. Months later, it may attract hungry birds to the berries if any develop.

Important: Winter honeysuckle is a “true” honeysuckle. It is not listed invasive in Tennessee and Virginia, but North Carolina and Texas forbids new plantings. Since it blooms so early in the year, e.g., compared to most honeysuckle species, few fruits or seeds develop. In southern locales where winters are mild, it seeds in prolifically.

Landscape use: clipped or informal hedge, screen or background border shrub.

Small Landscape Tree – Try Chinese Pistache

Posted by Hugh on January 17th, 2018

Compound leaf

Pistacia chinensis

Chinese pistache tree (Pistachia chinensis) is an underplanted small 30-35 foot landscape tree native to China, Taiwan and the Philippines (USDA hardiness zones 6b-9). It is related to the edible nut pistache tree (Pistachia vera).

Foliage consists of pinnate compound, dark green leaves (to 10 inches long), each leaf typically having 10-12 lanceolate leaflets (to 4 inches long). The tree displays a fine leaf texture. The small leaflets are an easy clean-up at raking time. Foliage is aromatic when bruised. The eye catching fall color is crimson red, bright orange, or occasionally yellow.

This tree species is dioecious, e.g a single tree is either male or female. Pistache blooms in April, but is not a standout compared to all shrubs and trees flowering at this time. Female flower clusters are nearly twice as wide as males. The non-edible fruits turn red in summer before ripening to blue-purple in winter. However, the berries (drupes, ¼ inches in diameter) are a food source for birds. Gray-brown bark on older trees peels to reveal salmon inner bark.

Chinese pistache grows in moist, compost rich, well-drained soils in full sun. It prospers in full sun but can handle partial shade. Verticillium wilt can become a serious problem in poorly drained soil. A 2-year old established tree tolerates summer heat, drought, and moderate air pollution. Annual pruning in early years is essential to maintain a symmetrical tree with good form.

If you are concerned about berries dropping on walkways, select a fruitless male clone, P. chinensis ‘Keith Davey,’ a 35-foot high tree with a crown diameter of 30 feet.

Four Top Rated Coreopsis You May Not Know

Posted by Hugh on January 14th, 2018

Coreopsis ‘Gold Standard’

C. ‘Gold Standard’

In 2016, Mt. Cuba Center in Greenville, Delaware reported the garden performance of 13 different perennial coreopsis (tickseed) species, hybrids, and related cultivars native to the eastern U.S. Over a period of three years, plants were assessed for their habit, floral display, disease resistance, and longevity. In the trial many popular tickseed cultivars performed poorly because of disease and winter survivability.

Four new selections were recognized and named because of their outstanding performance in the trial. The following plants, listed in order starting with the highest rated, are among the top-performing coreopsis.

‘Summer Sunshine’ coreopsis (C. palustris ‘Summer Sunshine’) is the highest-rated coreopsis in the 3-year trial. Vigorous mounds of foliage grow to 30 inches tall and remain lush, sturdy, and dense all season long. The attractive foliage erupts in late September with a sea of golden yellow flowers with dark central cones. The amazing display lasts for six weeks, providing an important late-season food source for pollinators. ‘Summer Sunshine’ is a rhizomatous selection that slowly increases in size by 2½ feet over three years. It has superior growth habit and disease resistance.
‘Flower Tower’ coreopsis (C. tripteris ‘Flower Tower’), appropriately named, towers over the competition at an astonishing 8 feet tall. This tall cultivar does not flop with thick, sturdy stems, standing up to the strongest winds. ‘Flower Tower’ was the tallest coreopsis in the trial and has the largest flowers (2½”). During the month of August, they create a wonderful display swaying atop the lofty stems. ‘Flower Tower’ is perfect for large-scale landscapes, but a challenge in average sized gardens. C. tripteris ‘Flower Tower’ is a rhizomatous selection that spreads very slowly– about 2 feet over 3 years.
‘Gold Standard’ coreopsis (C. tripteris ‘Gold Standard’) is a superior selection of tall tickseed (C. tripteris). C. tripteris grow typically to nearly 7 feet tall, has a floppy growth habit and subpar floral display. But ‘Gold Standard’, collected in Alabama by Mt. Cuba Center, is slightly shorter (5½ feet’ tall) and incredibly sturdy. In late July, multitudes of bright yellow flowers appear above the vigorous foliage, reaches its peak in mid-August, and floral display lasts over two months. ‘Gold Standard’, in fact the whole species exhibits excellent disease resistance, particularly powdery mildew, downy mildew, and leaf spot, that plague other coreopsis. ‘Gold Standard’ is a rhizomatous cultivar that spreads slowly– about 2’ over three years.
C. ‘Last Dance’
‘Last Dance’ coreopsis (C. integrifolia ‘Last Dance’) is a fall-blooming tickseed that has a superior uniformly compact habit over other forms of C. integrifolia. ‘Last Dance’ emerges slowly in spring and does not reach 1 foot tall until June, and is just 2 feet tall. The gold colored flowers are extra-large (2 inches) with thick pleated petals. It is the latest coreopsis to flower in October.

View the entire research report on Coreopsis on the MT Cuba Center website.

Photos furnished by MT Cuba Center, Greenville, DE.

Pest Alert: Deep Freeze Negatively Impacts Hemlock Adelgid Populations in the Smokies

Posted by Hugh on January 12th, 2018

Hemlock adelgid

GOOD NEWS! The recent cold snap is having a negative impact on the invasive hemlock wooly adelgids in the Smokies. Since 2002 this insect has killed millions of hemlock trees in the U.S. Biologists in the Great Smoky Mountains report that the recent spell of frigid temperatures has killed off overwintering hemlock adelgids.

Over 15 years ago, the hemlock woolly adelgid (HWA) invaded the Great Smoky Mountains National Park. This tiny Asian insect has killed millions of hemlock trees in the Eastern U.S. The pest gets its name from the white woolly coating that covers and protects the nymphs while they feast on hemlock trees.

Wooly adelgids complete a lot of their life cycle over the winter months. The severe dips in temperatures this winter are negatively effecting populations in the Northern areas of the U.S. and Canada. Insect mortality occurs when temps go down to 4 – 5°F.

The hemlock-killing bugs had been rebound the last couple of winters. A similar deep freeze back in 2014 also penetrated the insects’ woolly protection. “The big ‘polar vortex’ blast in 2014 and 2015 really helped us out with the adelgid. We had those prolonged weeks where the temperature was below zero in the higher elevations and killed a lot of them,” says NPS forester Jesse Webster.

Last year’s drought saw big population increases in HWA. “We really can benefit from some hard freezes in dry weather. Snow and ice can insulate insects. When they are directly exposed to the extremely cold air, that’s when their mortality rates are really high” says Webster.

Credit: this information originated from a news report from WBIR-TV in Knoxville, TN and has been edited.

Key Landscaping Tips

Posted by Hugh on January 11th, 2018

Hybrid rhododendron

Soil preparation

To develop a successful landscape plan, first do a walk-a-round before you start digging and planting. Record your landscape’s sun patterns, soil types, wind and water movement. This information will help you select the kinds of plants that will prosper under existing conditions.

Sun exposure shifts daily and seasonally. Observe the garden at different times to gain a better understanding of light exposures. Particularly note areas that receive full day sun or full shade. What percentage of existing trees and shrubs are deciduous and evergreen. Under deciduous shade, the fall and winter landscape may bathe in sunlight. In areas with partial sun exposure, identify where sunlight strikes an area at what time(s) of day as well as seasonally.

Soils may vary from one area of a landscape to another. Dig test holes in a variety of locations to determine the texture and color of soils. Is the landscape composed of sandy or loamy soils? Does it contain lots of clay? Soil type and drainage go hand-in-hand and impact the types of plants that should prosper in your landscape. Sandy soils drain very quickly, while clay soils are slow to drain. Many plants are also limited by soil pH, so it is a good idea to have the soil analyzed.

Water and Soil Drainage. In addition to soil type, topography and physical structures influence soil moisture. Low spots and areas surrounding downspouts tend to be wet, while the area beneath an overhang is commonly dry. Walk the garden after a rain to see where water collects and make note of seasonal rainfall patterns in your area. Do your region frequently experience seasonal drought; is your summer climate hot and humid? Are your winters generally snow covered or will ice storms damage tree branches?

Wind. Exposure to wind may vary considerably across a landscape. Some areas are likely exposed to strong winds while others may be protected by buildings, structures, or tall shrubs. For example, broadleaf evergreens such as camellias, rhododendrons, daphnes, and pieris are sensitive to drying winter winds. Understanding wind patterns will aid in positioning new plants at planting time.

Wildlife. What birds and animals are indigenous to your neighborhood? Do critters cause damage to plants? Consider deer, rabbits, raccoons, squirrels, moles, voles (field mice) which may relish your landscape and garden plants.

Common Street and Landscape Trees

Posted by Hugh on January 10th, 2018

Street tree planting of Ginkgo

Across the U.S. and Canada, city planners, landscape architects, and property owners now enjoy a wide selection of landscape trees to plant on city streets, along roadsides, and in yards and gardens. Over the past half century new and improved varieties (cultivars) are disease and pest resistant and exhibit better branching and architecture. We now know to avoid species with messy fruits or that produce excessive leaf litter. Most important is to select according to the tree size (mature height and branch spread).

Plant scientists and city arborists continue to evaluate tree selections that perform best in their areas. Below is a list of more than 50 common species that are currently planted across the U.S. THIS LIST IS NOT COMPLETE. Planting some tree species such as ash (Fraxinus), black walnut (Juglans), and callery pear (Pyrus) are on the decline because of pest and disease problems or weak branching.

Before planting a tree, reach out to local experts at nurseries and full-service garden centers or call the county/city Extension office. State universities, botanical gardens, and arboretums may also provide tree lists. Take a few minutes to look up for utility lines and telephone utility companies to locate buried lines.

List of Landscape Trees:

Japanese maple (Acer palmatum)

Norway maple (Acer platanoides)

Red maple (Acer rubrum)

Silver maple (Acer saccharinum)

Sugar maple (Acer saccharum)

Ohio Buckeye (Aesculus glabra)

Serviceberry (Amelanchier spp.)

Birch (Betula nigra)

Paper birch (Betula papyrifera)

Horsechestnut (Aesculus hippocastanum)

Northern catalpa (Catalpa speciosa)

American hornbeam (Carpinus carolinana)

Carpinus betulus ‘Fastigiata’

European hornbeam (Carpinus betulus)

Hackberry (Celtis occidentalis)

Eastern redbud (Cercis canadensis)

Yellowwood (Cladrastis kentukea)

Washington hawthorn (Crataegus phaenopyrum)

Green hawthorn (Crataegus viridis)

White ash (Fraxinus americana)

Green ash (Fraxinus pensylvanica)

Ginkgo (Ginkgo biloba)

Honeylocust (Gleditsia triacanthos)

Kentucky coffeetree (Gymnocladus dioicus)

Black walnut (Juglans nigra)

Red cedar (Juniperus virginiana)

Goldenrain tree (Koelreuteria paniculata)

Crape myrtles (Lagerstroemia x spp.)

Sweetgum (Liquidambar styraciflua)

Tulip poplar (Liriodendron tulipifera)

Southern magnolia (Magnolia grandiflora)

Southern magnolia

Crabapple (Malus spp.)

Blackgum, tupelo (Nyssa sylvatica)

Callery pear (Pyrus x calleryana)

Ironwood (Ostrya virginiana)

London plane, Sycamore (Platanus x acerfolia)

American sycamore, planetree (Platanus occidentalis)

White poplar (Populus alba)

Cottonwood (Populus deltoides)

Flowering cherries (Prunus spp.)

White oak (Quercus alba)

Bur oak (Quercus macrocarpa)

Pin oak (Quercus palustris)

Willow oak (Quercus phellos)

Northern red oak (Quercus rubra)

Black locust (Robinia pseudoacacia)

Japanese Scholar, pagoda tree (Styphnolobium japonicum)

Mountain ash (Sorbus spp.)

Japanese tree lilac (Syringa reticulata)

Bald cypress (Taxodium distichum)

Eastern arborvitae (Thuja occidentalis)

American linden (Tilia americana)

Little leaf linden (Tilia cordata)

American elm (Ulmus americana)

Lacebark elm (Ulmus parvifolia)

Japanese zelkova (Zelkova serrata)

Crypts (Cryptanthus) Are The Easiest Bromeliads To Grow

Posted by Hugh on January 7th, 2018

‘Elaine’ Cryptanthus at 2016 Philadelphia Flower Show

C. fosterianus-‘Liza-Vinzant’

Crypts (Cryptanthus spp.), members of the bromeliad family, are an ideal low care choice for house plant collectors. Currently, there are over 1200 varieties of Cryptanthus species and hybrids available today. Compare to other bromeliads, which grow in trees or rock outcropping, crypts grow in soil or rock ground. Plants prefer an airy, porous, moist soilless media favored by most tropical plants, including African violets, orchids, and ferns.

Most kinds of crypts grow in low-light conditions found in most homes. They benefit from daily misting, particularly during the winter month. Some can tolerate direct sunlight but need more frequent watering. Best foliage color is in bright diffused light source. Excessive direct sunlight may bleach out leaves or cause burn spots. Contrarily weak foliage and lose of color typical for the variety suggests that the plant needs more light. Fluorescent Gro-lights and new LED lights bring out their textured leaf color(s).

Like bromeliads, crypts make excellent office plants, in a temperature range between 60 to 85°F and tolerate temperature lows just above freezing. They will tolerate summer temperatures above 100 °F. if soil moisture and humidity are adequate. Many varieties thrive outdoors in shady areas of the garden in USDA zones 8-11. Fertilize crypts with a dilute solution perhaps ¼ to ½ package directions such as Miracle-Gro™ or Peters™. Crypts are relatively disease and pest free.

Crypts are reliable bloomers. Different species and cultivars bloom at different times of the year. Flowers are generally white although some have pink to lavender flowers.New plants are produce from offsets (pups) which form on stolons (runners) originating from the plant base. Offsets begin to develop when the mother plant initiates blooming or shortly thereafter. Many crypts make ideal hanging basket plant with the pups hanging off the pot edges.

Tree Cultivars That Do Not Produce Seeds Or Fruits

Posted by Hugh on January 4th, 2018

Aesculus x ‘Baumannii’

‘Ace of Hearts’ redbud – no seed pods

Perhaps you don’t like picking up messy fruits and seeds from your lawn in the fall and winter. Choose landscape trees that have seedless cultivars. A true seedless variety is an easy choice to avoid fruit cleanup.

Below are a few non-fruiting or seedless cultivars available at nurseries. Not all plants listed are recommended for all home landscapes. For example, avoid planting any species of ash (Fraxinus spp.) because of the threat of Emerald Ash Borer (EAB) infestaations. So do your homework before purchasing.

A few of my personal favorites include: ‘Autumn Blaze’ hybrid maple, ‘Espresso’ Kentucky coffeetree, any male ginkgo, ‘Slender Silhouette’ sweetgum, and ‘Ace of Hearts’ and ‘Don Egolf’ redbuds.

Boxelder (Acer negundo) – male cultivars ‘Baron’

Red Maple (Acer rubrum) ‘Flame’, ‘Northwood’

Silver maple (A. saccharinum) ‘Beebe Cutleaf Weeping’, ‘Silver Queen’, ‘Skinneri’

Hybrid maples (Acer x freemanii) ‘Celzam’, ‘Autumn Blaze’, ‘Jeffersred’ (nearly seedless)

Red horse chestnut (Aesculus x carnea) – Ruby, ‘Briotti’ (almost fruitless)

‘Baumann’ Horse chestnut (Aesculus hippocastanum ‘Baumannii’)

Redbud (Cercis canadensis) ‘Ace of Hearts’, ‘Flame’ (double flowered)

Chinese redbud (Cercis chinensis ‘Don Egolf’) – no seed

American persimmon (Diospyros virginiana) – male clones

American ash (Fraxinus americana) ‘Skyline’, ‘Autumn Purple’, others.

Green Ash (F. pennsylvanica), ‘Marshall Seedless’, ‘Summit’, others.

Kentucky coffeetree (Gymnocladus diocus ‘Espresso’)

Ginkgo (Ginkgo biloba), use male cultivars such as ‘Halka’, ‘Autumn Gold’, ‘Princeton Sentry’

Honeylocust (Gleditsia triacanthos f. inermis) ‘Fairview’, ‘Green Glory’, ‘Imperial’, ‘Moraine’, ‘Shademaster’, ‘Skyline’, ‘Sunburst’

Hollies (Ilex spp.) -male clones

Sweetgum (Liquidambar styraciflua) ‘Rotundiloba’, Happidaze™, ‘Slender Silhouette’

Crabapple (Malus spp.), ‘Spring Snow’ (fruitless, but fire blight and apple scab susceptible)

‘Chapparal’ Weeping Mulberry (Morus alba) ‘Chaparral’

Kwanzan cherry (Prunus serrulata ‘Kwanzan’)

Black locust (Robinia pseudoaccia ‘Frisia’)

Sassafras (Sassafras albidum)

Steps To Making Gardening Easier

Posted by Hugh on December 30th, 2017

Hydrangea arborescens ‘Incrediball’

Gomphrena

Take an inventory of your gardening time, talley up of costs, and develop a plan how to make your garden space more beautiful with less work and cost to you.

Plant Smarter Simplify! For example, in my zone 6 garden, bigleaf hydrangeas disappoint tow out of three years and they’re water hogs in the summer. Smooth (AG) hydrangeas (like ‘Incrediball’ hydrangea pictured), and Panicle hydrangeas are so much less demanding and require far less water.

Choose annuals and perennials that are pest and disease resistant, consume less water, and are self-cleaning like gomphrena (pictured), scaevola or celosia.

Some plants are poisonous to humans and pets. Rhododendrons and Oleanders are toxic to dogs and cats. Also, rethink using pesticides on lawns where pets and children play.

Use more native plants, but also include many low maintenance non-natives that are well behaved. Garden to attract more pollinators, particularly bees, butterflies and birds.

Mulch smartly to reduce watering and weeding.

Plant “waves of ground covers” such as ferns, fairy wings (epimediums), and hostas to discourage weeds and provide a tapestry of foliage and flowers.

Plant shrubs and ornamental trees that require much less maintenance. Perhaps, it is a small long blooming shrub that can enliven an area that currently takes 4-5 perennials at twice the labor.

Downsize your growing area. Plant a rain garden or prairie border. Plant more perennials than annuals.

Emphasize safety.

Don’t strain your back or knees.

Prune less by selecting slower growing compact plants.

Grow more in raised beds that are at a comfortable working height.

Choose better quality ergonomic tools.

Summary: Rethink how you garden… Redesign your outdoor living area…More seasonal color…Less maintenance…Enjoy your garden.