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

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.

Deck The Halls With These Ten Festive Plants

Posted by Hugh on December 24th, 2017

Display at Biltmore Estates in Asheville, NC

Celebrate the holiday with these live plants, some of which you receive as gifts. These houseplants can stand alone or complement the festive holiday decor:

Poinsettia. No other houseplant captures the Christmas spirit more than poinsettias.
Thanksgiving/Christmas Cacti (Schlumbergera bridesii or S. truncata) – these easy to care for dependable flowering cacti (they’re really succulents) come in red, pink or white colored blooms.

Amaryllis is a bulbous plant that blooms in winter season or program to flower in any season. Large flowers available in vibrant reds, orange tones, pinks, snowy white, or bicolors.
Amaryllis + daffodils

Norfolk Island Pine. Mini-Christmas trees have become a holiday staple at garden centers. Indoors, they may grow up to 12 feet in height. They can spend summers outdoors under the shade of a shade tree.

Kalanchoes are true succulents, so do not overwater and allow excellent soil drainage. They bear lovely foliage and long lasting flowers that come in red, orange, pink, purple, yellow, white and just recently bi-colored varieties.
Cyclamen- their lovely mottled, heart-shaped leaves and red, pink, or white flowers will beautify spaces in your home or in protected outdoor areas where nightly temperatures do not drop below 37 °F.
Bromeliads – one of the easiest house plants to grow. They don’t ask for much light. Mist the air around them several days per week. Flowers are very showy and young plants (pups) form that become the “grandchildren” of your plant.
Tillandsias – which are bromeliad relatives are frequently sold as “Air Plants” because plants don’t have roots and are not potbound. All plant(s) ask for is a daily misting or weekly one hour soaking in the sink or bucket of water.
Sedums – available in pots or planted in changeable frames suitable for wall hanging either for room interiors or outdoors (hardy types).
Paperwhites – miniature white daffodil blooms are highly fragrant. Simply give plenty them of water, and you’ will be rewarded with 4 weeks of beautiful winter white blooms

During the spring-summer seasons feed most plants (not tillandsias) monthly with a weak solution of Miracle -Gro or an equivalent product. Otherwise, water plants weekly.

Five Evergreens For Small Garden Spaces

Posted by Hugh on December 21st, 2017

Thuja occid ‘DeGroot Spire’

‘Green Arrow’ Alaskan cedar

The following five evergreen shrubs are smaller versions of the larger growing species. They make a better fit in smaller urban gardens.

Gyokuryu Japanese cedar (Cryptomeria japonica ‘Gyokuryu’) is a fast-growing, broadly conical selection with coarse bluish-green evergreen foliage. The needles are highly ornamental and remain bluish-green through most of the winter in zone 6 and points south. Neither the flowers nor the fruit are of little significance. The peeling reddish bark is an added plus. After 10 years of growth, a mature specimen will measure 12 feet (4 m) tall and 8 feet (2.5 m) wide, an annual growth rate of 12 to 15 inches

De Groot Spire arborvitae (Thuja occidentalis ‘DeGroot Spire’) – is the smaller version of Emerald arborvitae™. It is a dwarf, slow-growing cultivar with an upright, pyramidal habit and twisted, scale-like, medium green foliage. De Groot Spire can reach 15-20 feet tall and 4-5 feet wide in 15-20 years.

Dawn redwood (Metasequoia glyptostroboides) -two selections:

‘Northlight’ (‘Schirrmann’s Nordlicht’) is a dwarf shrub form of dawn redwood. It forms a rounded crown of closely spaced stems. Foliage is variegated with irregular cream-white markings.
‘Little Giant’ | Little Giant Dwarf Dawn Redwood- small erect tree to 15 feet, a mini of its lovely parent, with light chocolate brown bark and feather-light deciduous needles, can grow up to 10 inches annually.

Alaskan cedar (Chamaecyparus nootkatensis) – two cultivars to choose:

‘Van den Akker´is a Northwest native that is an extremely narrow upright. It may reach over 20 feet tall while remaining only about 1 – 1/2 feet wide. It has strongly pendulous (weeping) branches are covered with scale-like blue green foliage.
‘Green Arrow’ exhibits an extremely narrow growth habit. Lateral branches hang close to the trunk. This vertical evergreen is perfect for small gardens or tight spaces.

Bald cypress ‘Peevee Minuret’ (Taxodium distichum) is an exceptional dwarf selection of our large native bald cypress. Branching of this pyramidal tree form is upright like its larger kin. Feathery, dark green, deciduous foliage (needles) turn a rust color in fall before falling. Papery, chestnut-red bark is an added winter feature. Peevee Minuret grows 5-6 feet tall in 10 years.

Poinsettias – Best Of Show**

Posted by Hugh on December 16th, 2017

Poinsettias In Greenhouse

‘Red Elf’ poinsettia (photo from NC State University, Raleigh)

This holiday season poinsettia breeders continue to give plant buyers lovely colors, patterns and shapes. Recently, at Mitchell’s Nursery & Greenhouse in King, North Carolina, Judy Mitchell got the word out about their annual Poinsettia Open House. Close to 400 people attended their openhouse and evaluated the 10,000 poinsettias, choosing which of the 79 varieties were their favorites.

Here are the results:

Top 5 Reds

Red Elf^#
Freedom Red
Jubilee Red
Christmas Feel Merlot
Majoris Red

Top 5 Whites:

White Poinsettia Tree at Biltmore Estates, Asheville, NC

1.Polar Bear

2.Premium Polar*

3.Whitestar*

4.Snowcap

5. Mars White

*Tied for 2nd

Top Pink:

Maren
Venus Hot Pink
Luv U Pink
Luv U Pink Hot
Freedom Pink

Top 5 Novelties

Ice Punch
Red Glitter
Tapestry
Ruby Frost
Orange Spice

^#Red Elf is designed for the small pot market. Plants flower early season with medium red bracts that are upright facing.

**Source: BUZZ e-newsletter, Ellen Wells editor, oublished by BallHort

Protect New Trees From Winter Sunscald

Posted by Hugh on December 13th, 2017

Newly planted tree + mulching

Tree wrapping (Photo from A.M. Leonard, Inc)

Across the northern U.S. and Canada, cold temperatures can damage many plants. Wide fluctuations in temperature can be particularly detrimental to newly planted landscape and fruit trees from late fall to early spring. Street trees are particularly susceptible.

Sun scald is described by elongated, sunken, dried, or cracked areas of dead bark, usually on the south or southwest side of the tree. On cold winter days, the sun can heat up bark to the point where cambial activity is stimulated. At dusk or when the sun is blocked by a cloud, hill, or building, bark temperature drops rapidly, killing the active tissue

Young trees, newly planted trees, and thin-barked trees (cherry, ornamental plum, crabapple, honey locust, linden, maple, and mountain ash (Sorbus) are most susceptible to sun scald. Winter pruned trees that have had their lower shade branches removed, or have been transplanted from a shady to a sunny location are also susceptible to sun scald. Older trees are rarely injured by sun scald because their outer bark is thicker.

Sun scald can be prevented by wrapping the trunk with a commercial tree wrap or any other light-colored material. The wrap should reflect the sun and insulate the bark so temps do not wildly fluctuate. Spiral white plastic bands, available at many full service garden centers, also protect against deer and rabbit browsing (nibbling) on the bark. Wrapping 3-4 sheets of newspaper around the trunk also works. Over the first two years best management practice is to remove all wrappings in the spring and reinstall in the fall. Do not leave the wrap on longer than necessary because it could trap moisture and become a haven for pests.

Newly planted thin-barked species should be wrapped for their first two winters, but some may need covering for up to five winters, sometimes more.

Care of African Violets

Posted by Hugh on December 8th, 2017

African violets at Garden Center

African violet gift plant

African violets (Saintpaulia ionantha) or AVs are among the easiest flowering house plant to grow. They need indirect moderate to bright lighting and moist well-drained potting soil. Grow plants in plastic pots and not in clay (terra cotta). AVs should be repotted annually.

Here are some additional cultural tips:

Room temperatures: AVs thrive at room temperatures between 65 to 80 °F. Set plants away from cold drafty windows.

Watering: Keep soil moist, but permit soil to dry out 4-5 days between waterings. Water plants mostly from the bottom with room temperature water. Allow plant to absorb water from a saucer or tray for 20-30 minutes and drain off the extra. Cold water straight from the tap can cause leaf spotting and may contain harmful chlorides or fluorides. Do not allow plants to sit in water too long as AVs are susceptible to root rot diseases.

Plant nutrition: Feed with water soluble fertilizers such as Miracle-Gro® or Optimara® African Violet Food at one-half the package directions; feed the dilute solution twice as often from mid-February thru September. Cut back feeding to once monthly during the fall and winter months (October thru early February). If tap water contains fluoridated or chlorinated, store water in an open top container overnight to allow the chloride or fluoride gas to escape.

Lighting: Indirect sunlight or artificial lighting is best. Plants stop flowering and leaves become chlorotic (yellow) when they don’t receive enough light. Leaves and stems also stretch out and weaken. Too much sunlight can cause leaves to sunburn, and leaf stems (petioles) to droop downward; variegated leaf varieties may turn fully green. If light source is from a nearby window, rotate pots one-quarter turn weekly, perhaps after you’ve watered.

Many hobbiests grow their AV collection under special “grow lights” for 10-12 hours a day. Grow lights are generally mounted 18 to 20 inches above plants or 10 to 12 inches above small cuttings or miniature varieties. Connect lights to a timer, so they go on and off even when you are away.

Humidity/Air Circulation: Group plants close together but do not crowd them. Give violets enough room to grow and to maintain sufficient air circulation in order to prevent the growth of potentially harmful Botrytis and Powdery Mildew diseases. A room humidifier will also help over the winter and summer months when heat and air systems are drying out the room environment.

New: The Bushel and Berry Collection Of Patio Fruits

Posted by Hugh on December 4th, 2017

Bushel and Berry™ Collection Raspberry Shortcake

Back in late 2016 Star® Roses and Plants* purchased the company formerly known as BrazelBerries®. In 2017 they have rebranded the plant offerings into the new Bushel and Berry™ Collection. Beside the old favorites, a new collection of edible berry plants are available at participating garden centers nationwide.

I have successfully grown two varieties on the sunny portion of my deck here in northeast TN (USDA hardiness zone 6-b). The spring purchased plants bloomed and produce fruits which were delicious. The Bushel and Berry Collection are easy-to-grow and ask for very little maintenance other than watering and fertilizing. Disease and insects did not trouble me my first year. I can’t promise that this will continue in future years. My plants were covered with cheese cloth as fruits began ripening for bird-proofing.

According to Layci Gragnani, program manager for Bushel and Berry, “the collection has a new look reminiscent of the biodegradable berry baskets found at farmer’s markets.” Currently, The Bushel and Berry collection includes seven varieties:

Raspberry Shortcake® – thornless dwarf raspberry

Peach Sorbet® blueberry – delicious fruits plus red fall leaf color

Jelly Bean® blueberry –dwarf plant with attractive red fall leaf color

Blueberry Glaze® – small dark berries and red fall leaf color.

Pink Icing™ blueberry – yummy fruits in summer and fall foliage

Perpetua® blueberry – double cropping (2 harvest times)

Baby Cakes™ – thornless dwarf blackberry.

Three growing tips (from me):

Repot in late winter to a slightly larger decorative pot and remove (prune) off old canes and any dead shoots.
Fertilize with a water soluble products like Espoma™ or Miracle-Gro™ bi-monthly from March through August
Place fine mesh netting over pot(s) as fruits begin to ripen.

*Star® Roses and Plants also markets the Knock Out® Family of Roses as well as Drift® Roses.