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

Japanese Cornel – Notable Cultivars

Posted by Hugh on February 11th, 2022

*Cornus officinalis* at Biltmore Estates in Asheville, NC

Starting in late February, Japanese cornel (C. officinalis) burst into bloom with clusters of yellow flowers (zones 5–8). Native to Japan, China, and Korea, this lovely small tree (or large shrub) is one of a few plants that is an early harbinger of spring. Here are notable cultivars:

‘Sunsphere’ grows 20-25 feet high and is an exceptional heavy bloomer with its bright yellow flowers. Sunsphere was found and named by Mike Stansberry in Knoxville, TN. Flowers are rarely injured by low night wintry temperatures still common in late February and March across the Southern Appalachian region (USDA zones 6 and 7). This small tree can be purchase from Beaver Creek Nursery in Knoxville, TN as well as from other on-line nursery source

‘Kintoki’ Japanese cornel dogwood (Cornus officinalis ‘Kintoki’) is another fine selection. Kintoki grows more as a large shrub than tree-like @ 15 to 20 feet tall and wide. Training this shrub into a small tree is not difficult. Early spring masses of brilliant yellow blooms are followed by stunning red, cherry-like fruit that ripen in late August.

Kintoki is rated as one of the better cornelian cherries in the southeast U.S. The plant is notable for its heavy flowering, exceptional high gloss seasonal foliage, and exquisite exfoliating bark that gets better with the passing of time.

Japanese cornel grows in any average well-drained soil and in full sun to partial shade. Spring-summer foliage is dark green, and autumn colors varying from light yellow to reddish purple before falling. As the grayish outer bark ages, it chips off in tiny strips, exposing the yellow-orange inner wood. In late summer the cherry red drupe fruits have colored up and are consumed by foraging birds.

Eleven Popular Perennials In The U.S.

Posted by Hugh on February 6th, 2022

Today’s most popular perennials are ones asking for low maintenance and have few to no bug or disease problems. Cutflowers may be used in fresh cut and in dried arrangements.

Coneflowers (Echinacea x) – native coneflowers are tough and pretty; flower colors: purple, white, orange, red, yellow. Compact coneflower series (16 to 30 inches tall): Sombrero®, Artisan™, PowWow®, and Cheyenne Spirit® for non-stop blooming June to September; spent flower cones visited by goldfinches or other birds over winter. (Z 4-9)

Black-Eyed Susan (Rudbeckia) – heavy-blooming native perennial from early summer to frost. Highly recommended new cultivar ‘American Gold Rush’ is disease resistant, heavy bloomer, and should not reseed all over your garden. Deer-free and drought- and heat- tolerant. (Z 3-9)

Hostas (Hosta spp.) also known as plantain lily – the leading shade perennial prized for their large, tropical-looking leaves that come in an array of sizes, shapes, and colors ranging from chartreuse to blue-green to bicolor. Floral spikes of white, lavender, or pale purple appear over the summer months. (Z 3-9)

Daylily (Hemerocallis) varieties are available in almost shape, size and color imaginable. Daylilies are exceptionally dependable long-lived perennials. Ask local gardening friends for a list of their regional favorites. (Z 3-9)

Bee Balm (Monarda) aka Oswego Tea – this old-fashioned perennial beloved by gardeners is visited by hummingbirds, butterflies and bees. Flowers come in red, pink and lavender all summer long if deadheaded. Try tall-growing ‘Jacob Kline’ for its 3+ feet high, mildew-resistant, scarlet red flowers and new compact (14-18 inches) Pardon Me® series. (Z 4-8)

Herbaceous Peony (Paeonia) – one of grandma’s favorites and currently enjoying a resurgence in popularity. Flowers are outrageously gorgeous, some varieties measuring 10 inches across. Color range of white, red, purple, peach, and many pink shades. (Z 4-7)

Red Hot Poker (Kniphofia), aka Torch Lilies and Tritoma – prized for their tall, show stopping flower spikes in bright red, orange, yellow, and other colors; full to partial sun and well-drained soil. Cultivar sizes range from dwarf (14 inches) to tall 3 feet tall. Popular series include Pyromania™, Poco™, Popsicle™, and Echo™. (Z 6-9)

Tall garden phlox (Phlox paniculata) stand tall height and invite butterflies to large, fragrant clusters of pink, red, purple or white flowers from mid- to late- summer; select powdery mildew resistant varieties like ‘David’, ‘Glamour Girl’, and ‘Jeana’. (Z 3-8).

Shasta Daisy (Lecanthemum x superbum) – bright white or creamy white daisy blooms such as ‘Becky’, ‘Whoops-a-Daisy’ and ‘Banana Cream ll’ in early- to mid-summer. (Z 5-9)

Lenten Rose (Helleborus x) – winter bloom from late December (H. niger) onward into early April and these evergreen perennials are usually deer resistant. Their single or double flowers welcome pollinating bees back into your garden. (Z 4-9)

Daffodils (Narcissus) – prized for their cheerful yellow/white, trumpet-shaped flowers that herald the arrival of spring. Plant bulbs in fall and they bloom for many springs to come; hundreds of types of daffodils to select from yellow, orange, white, and bicolors. (Z 3-9)

Create A Garden With Four Seasons Appeal

Posted by Hugh on February 1st, 2022

Winter blooming paperbush (*Edgeworthia chrysantha*)

‘Winter King’ hawthorn laden with fruits on a cool February day

Your garden should be a year-round enjoyment and you should design it to reflect that. Many trees and shrubs offer multi-seasonal attraction. Several years back I designed a series of walking paths to network through my garden to capture its 12-month natural beauty.

Planning next year’s garden? Look for calendar gaps in your own landscape and what plants fill that gap of time. Choose an outdoor site where the seasonal enjoyment can be viewed from inside your home. For example, plant Japanese maples, flowering dogwoods and cherries, summer flowering hydrangeas and Rose of Sharons (Hibiscus syriacus), and fall-winter flowering camellias and colorful holly berries within view from a patio window so you may enjoy it seasonally from inside the warmth of your home in winter.

On a frigid wintry day, curl up with a good book indoors while staring out a window at the vee-branch architecture of a clump river birch or crape myrtle, the mid-winter flowering Chinese paperbush (Edgeworthia) that may be enjoyed all four seasons. During February-March, vernal and Chinese witchhazels are blooming; winter aconites (Eranthis) and snowdrops (Galanthus) are in flower, and daffodils, crocuses, and other bulbs are poking through.

What about planting trees and shrubs with brightly ornate fruits over the fall and winter seasons. ‘Winter King’ hawthorn (Crataegus viridis) or winterberry holly (Ilex verticillata) are loaded with ruby red fruits. Plant a tree with attractive winter bark such as redtwig dogwood (Cornus stolonifera), flowering cherry (Prunus x yedoense), or paperbark maple (Acer griseum) nearby a window to be viewed from indoors on a cold or snowy winters day. How about the gray muscular bark of native hornbeam (Carpinus carolinana) or the vertical architecture of ‘Slender Silhouette’ sweetgum.

Enjoy your garden 12-months a year. Invite nature indoors by filling vases with dried flower heads from hydrangeas, various perennials, or ornamental grasses to decorate a table or mantle. How about trekking through the winter garden with hot chocolate in hand. Construct a series of walking paths made from wood shavings, pine needles, chat (fine gravel), or 16-18 inch concrete squares.

Fresh Spring Foliage of ‘Purple Ghost’ Japanese maple

Lacebark Pine

Posted by Hugh on January 28th, 2022

Lacebark pine (Pinus bungeana) (USDA hardiness zones 4-8) is arboreal mid-sized gem is a lovely 3-needle pine. It is a slow-growing pine with an absolutely exquisite exfoliating patchwork bark which becomes more attractive as the tree ages. Some of the best specimens that I have witnessed are planted on the New York Botanical Gardens in the Bronx, NY.

Lacebark pine grows into a 30-50 feet tall pine with narrow upright branching. Gardeners and landscapers may start out planting an affordable 2 – 3 feet multi-branched shrub. The slow growth rate, initially 4-5 inches annually, almost doubles after 4-5 years on-site. The lovely cinnamon-colored candles tip the branches in May, similar to candles decorating a cake. When fully expanded, 3 needle clusters -long bristly needles measure 2-3 inches long and are sharp to the touch.

Lacebark requires no special care other than fertilizing in the early spring and mulching until it is established after 2 years. Plant lacebark in full sun and above-average garden soil that is well-drained. An older tree exhibits moderate drought tolerance.

Bark mottling begins after 8-10 years, but the real show is many more years away down the road. A young patient gardener may opt to prune off a few side branches for a peek of the exfoliating bark pattern within. Young tree bark tends to color olive green and gradually bleaches out to milky white many years hence.

Most potentially serious disease and insect pests may be avoided through wise siting and care. This is a specimen that must be sited. Select a visible landscape location which is frequently visited, such as near a patio, carport, driveway or a window which looks out at lacebark.

Two highly rated cultivars are ‘Rowe Arboretum’ and ‘Compacta’, both known to mature more compact size-wise. A third multi- trunked form is ‘Silver Ghost’; these multi-trunked forms exhibit exfoliating bark green bark color with irregular whitish or brownish patches. The bark is dotted much more white patching than the species.

Lacebark pine and cultivars can be purchased from specialty mail-order nurseries via the internet. Mature height and width of cultivars are 20 feet by 15 feet. Lacebark is a long-term investment, an evergreen that you and future generations will cherish for its exquisite patchwork bark.

More Cool Small Flowering Shrubs

Posted by Hugh on January 23rd, 2022

For many urban gardeners, landscape space is very limited. Here are several showy shrub choices along walkways and perennial border, and in deck and patio containers. Each year the list of dwarf shrubs continues to get longer. They are low maintenance, including very little annual pruning.

Shrub Roses – like Drift™ and Flower Carpet™ roses- are just excellent example. These perfectly shaped tiny roses have mostly clean, healthy foliage that stay under 2 feet in height (zone 4-9). They are moderately resistant to rose rosette virus. Some gardeners grow them as perennials.

Small hydrangeas like Tiny Tuff Stuff and Wee White smooth hydrangeas, Date Night weigela, dwarf chaste tree (Vitex), and several more that are newly introduced. Here are some featured tiny shrubs that you’ll like.

Date Night™ Electric Love’ Weigela – only 2-3 feet tall and 3 feet wide compact and vibrant red flowers and dark green foliage; plant it along a walkway or as the star of a decorative patio pot (zones 4-8).

Fine Wine™ Weigela is a shorter version of the variety Wine and Roses, only 2-3 feet tall and wide, deep burgundy foliage and deep pink spring flowers, that will re-bloom in summer (zones 4-8).

Invincibelle Wee White™ Hydrangea (Hydrangea arborescens ‘NCHA5’) produces large pure white flowers from early summer to frost, held upright on sturdy stems; forms a neat 2-3 feet mound (zones 3-9)

Tuff Stuff™ Hydrangea (Hydrangea macrophylla var serrata ‘MAK20’) grow only 2 – 3 feet high and wide with large, heart-shaped, bright green serrated foliage in spring and summer, that turns rich shades of bronze, burgundy, and carmine in autumn; lacecap pattern of tiny fertile flowers (dark red) in a cluster surrounded by larger, sterile florets (magenta-pink) flowers most of the summer. (zones 5-9).

Bobo Panicle Hydrangea (Hydrangea paniculata Bobo) -3-4 feet tall with white flowers that start blooming in mid-July in Tennessee.

Bellini™ Crape Myrtles (Lagerstroemia indica Bellini™ – compact series that bloom earlier, in a choice of delicious colors; plant near your foundation, or as a low shrub border, or in a mixed garden (zones 6-10).

Blue Diddley™ Vitex (Vitex agnus-castus) – blue summer flowers on a 3-6 feet tall compact plant (zones 5-9).

‘Tiny Wine’ ninebark (Physocarpus orbiculatus) – dwarf 3-5 feet ninebark that is smaller than most ninebarks with dark bronze-maroon foliage spring thru fall and white flowers in late spring (Zones 3-7).

Four Tree Conifers Which Should Be Planted More

Posted by Hugh on January 16th, 2022

Nordmann fir (Abies nordmanniana), aka Caucasian fir, is native to the Caucasus Mountains (USDA hardiness zones 4-6). This dense pyramidal conifer grows to 50 feet tall and 20 feet wide and are typically branched to the ground. Their flat dark green shiny needles (up to 1 ¼ inches long) feature two white bands on the underside. Bark is charcoal gray. Their upright cylindrical dark reddish-brown cones measure up to 6 inches long.

Glossy waxy clean needles of Nordman Fir

Best grown in rich, consistently moist, acidic, well-drained soils in full sun to part shade. Best in full sun. Trees grow poorly in heavy clay soils. Trees are native to cool climates, and are not recommended for planting in the hot and humid summer conditions south of USDA Zone 6.

Korean fir (Abies koreana) is a compact, conical to pyramidal evergreen conifer that slowly grows over time to as much as 50 feet tall. Korean fir is for the landscape in cool summer climates. It is native to the mountains of South Korea (USDA hardiness zones 5-7). Branches are densely clad with short but broad needles (to 3/4″ long) that are shiny dark green above and silver beneath. Purple cones (to 3″ long) are produced when the trees are quite young. As is distinctive with the firs, the cones appear upright on the branches.

No serious insect or disease problems. Occasional insect pests include balsam woolly adelgids, bark beetles, spruce budworms, aphids, bagworms and scale. Spider mites may occur in hot conditions. Trees are not tolerant of urban pollutants.

Hiba Arborvitae (Thujopsis dolabrata) is a conical needled evergreen native to Japan in the cypress family. The bright green densely packed needles provide color and winter interest in the garden. Plant in full sun to partial shade in moist, well-drained, neutral to alkaline soils. This tree does not tolerate dry soils. Its mature size is 30-50 feet tall x 15-30 feet wide. It produces tiny thick brown and violet with white wax ovoid seed cones.

*Thujopsis* on East TN State University campus, Johnson City, TN

‘Nana’ – aka dwarf Hiba Arborvitae, is a compact, mound-shaped evergreen shrub with shiny dark green foliage all season long and good form. It is a great evergreen accent for home gardens. The scale-like leaves remain dark green throughout the winter. Flowers or cones are not ornamentally significant.

Golden larch (Pseudolarix amabilis) is native to coastal mountain areas in southeastern China. Pseudolarix (means false larch) is an attractive large specimen tree with excellent needled foliage and fall color. This deciduous conifer tree grows 30-60 feet tall and is slow-growing and broadly-conical with horizontal branching and drooping branchlets. The soft green foliage turns golden yellow in fall before dropping. Needles (to 2.5” long) appear primarily in tuft-like clusters on spur-like short shoots. Cones (2.5 – 3 inches) stand erect reddish brown fruiting cones. Bark on mature trees is fissured and reddish-brown.

Golden larch on North Carolina Arboretum, Asheville, NC

Golden larch thrives in moist, acidic, organically rich loam feet and in full sun. The tree is tolerant of light shade, but intolerant of full shade. Avoid limestone soils. Best sited in a location protected from strong winds. This tree may struggle summer weather is exceptionally hot and humid, but generally outperforms common larch (Larix decidua). It has no serious insect or disease problems.

So Many Great Amsonias

Posted by Hugh on January 11th, 2022

Amsonias, commonly called blue star, are a group of easy-to-grow, long-lived native perennials. These highly dependable plants offer three-seasons of landscape interest: showy, long-lasting blooms in spring (mostly in May); threadlike green foliage in summer; and yellow foliage in fall.

Fringed Bluestar (*Amsonia ciliata*) at Mt Cuba Center in Delaware

Amsonias are native primarily to North America and belong to the dogbane plant family (Apocynaceae). This clump-forming perennial has narrow, alternate leaves and clusters of 5-petaled, light blue flowers. Elongated, pod-like fruits later develop filled with hard black seeds.

Amsonias prefer moist, loamy, well-drained soils, including clay soils and
in full sun to part shade. One year old plants are moderately drought resistant and wonderfully water-wise. Plants standup taller, sturdier, and more flowering in full sun. In partial shade and/or in rich soils, plants often open up (floppy) and frequently require staking. Foliage tends to take on brighter golden hues in the fall. Midday shade protection in hot Southern climates promotes longer-lasting flowering.

For a neater appearance and to promote a bushier habit, cut back stems by 1/2 to 1/3 into a neat mounding habit after flowering. Newer dwarf cultivars do not require staking or cutting back. Once established, amsonias are moderately drought-tolerant.

Fall color of Arkansas amsonia (*Amsonia hubrichtii*)

Amsonia flowers attract butterflies, hummingbird moths, and a number of bee species. Ruby-throated hummingbirds are also occasional visitors. Amsonias are not subject to disease or pest problems, including deer and rabbits.

There are several species of bluestar (3 listed here). Tidy foliage and a striking vase-shaped plant habit allow bluestars to perform well as either an accent plant or in mass plantings. Smaller varieties work well in containers.

Warning: Plant sap can be mildly irritating and wearing protective gloves is advised. Bluestars may be divided in late summer or early fall. Stem cuttings can be taken after flowering and rooted.

Three Popular Amsonia Species

Arkansas Bluestar (Amsonia hubrichtii) is noted for its lovely narrow, thread-like, and glaucous (hairy) foliage. Foliage that turns brilliant gold in autumn. Powdery blue, 1/2 inch wide star-like flowers appear in terminal clusters in late spring atop 2 – 3 feet tall stems. (Zones 5-8)

Eastern blue star (Amsonia tabernaemontana) is known by a number of other names including willow amsonia and blue dogbane. Its light blue flowers appear in mid- to late spring and light secondary bloom often occurs in late summer/fall. Dense foliage starts off lime green and matures dark green. Plants grow 2-3 feet tall with larger coarser textured leaves than A. hubrichtii. Cultivars: ‘Storm Cloud’ and ‘Blue Ice’ (hybrid). (Zones 3-9)

Fringed bluestar (Amsonia ciliata), aka downy amsonia, grows to 2-3 feet tall with terminal clusters of star-like, light blue flowers in May atop generally erect stems clad with narrow, almost needle-like, fine-textured, green leaves. silvery, fuzzy hairs cover new leaves and plant stems. Foliage turns mixed shades of yellow in fall. Zones 5-9

2022 Perennial Plant Of the Year – Little Bluestem

Posted by Hugh on January 6th, 2022

The Perennial Plant Association (PPA) has named its 2022 Perennial of the Year — Little Bluestem (Schizachrium scoparum) (USDA hardiness zones 3-9). This ornamental grass was chosen because it is suitable for a wide range of growing climates, is low maintenance, and offers multiple-season interest.

Seasonal Transition in Color (Hoffman Nursery, Inc.)

This North American prairie native grass is adaptable to many growing conditions. It is a warm season clumping grass that features blue tones in its summer foliage and a beautiful array of fall colors.

Little bluestem thrives in fall sun to partial shade and in average to poor dry soils. It is also a larval host to some species of butterflies and moths. It grows 3-4 feet high and around 1-2 feet wide. Avoid wet soils. Resistant to deer & rabbit browsing.

PPA board members selected several outstanding cultivars based on plant habit, foliage, and fall color well in several regional areas of the U.S. including: ‘Jazz’, ‘The Blues’, ‘Standing Ovation’, ‘Blue Heaven’, and ‘Carousel’. The cultivars were bred to be bluer in color and more upright in form.

This ornamental perennial warm-season, clumping grass has silvery-blue stems (particularly at the base) and leaves, making it an attractive addition to the landscape.

Little Bluestem is an excellent plant for wildlife. It serves as the larval host for several skipper butterfly species including Dusted Skipper, Cobweb Skipper, Ottoe Skipper, Indian Skipper, Swarthy Skipper, and he Crossline Skipper. Other insects that feed on Little Bluestem include grasshoppers, Prairie Walkingsticks, the leaf-mining beetles, thrips, spittlebugs, and leafhoppers. The seeds of this grass are eaten by songbirds. Little bluestem provides necessary overwintering habitat and food sources for many insects and birds. Female bumble bee queens nest at the base of bunch grasses, like Little Bluestem, where they are protected until they emerge in the spring.

Planting ideas: a lovely grassy texture for the middle of a perennial border, to soften the edge of a garden pond, or wind it through a naturalistic planting.

Information sources: Perennial Plant Association and American Horticulture SocietyW

‘Standing Ovation’ little bluestem

2022 Perennial Plant Of the Year – Little Bluestem

Posted by Hugh on January 3rd, 2022

2022 Perennial Plant Of the Year – Little Bluestem

Summer/Fall Photo credit: Proven Winners

The Perennial Plant Association (PPA) has named its 2022 Perennial of the Year — Little Bluestem (Schizachrium scoparum) (USDA hardiness zones 3-9). This ornamental grass was chosen because it is suitable for a wide range of growing climates, is low maintenance, and offers multiple-season interest.

This North American prairie native grass is highly adaptable to several landscape situations. Little bluestem is a warm season clumping grass that features blue tones in its summer foliage and a beautiful array of fall colors.

Little bluestem thrives in fall sun to partial shade and in average to poor dry soils. It is also a larval host to some species of butterflies and moths. It grows 3-4 feet high and around 1-2 feet wide. Avoid wet soils. Resistant to deer & rabbit browsing.

PPA board members selected several outstanding cultivars based on plant habit, foliage, and fall color well in several regional areas of the U.S. including: ‘Jazz’, ‘The Blues’, ‘Standing Ovation’, ‘Blue Heaven’, and ‘Carousel’. The cultivars were bred to be bluer in color and more upright in form. Select the variety that best performs where you garden.

This ornamental perennial warm-season, clumping grass has silvery-blue stems (particularly at the base) and leaves, making it an attractive addition to the landscape.

Little Bluestem is an excellent plant for wildlife. It serves as the larval host for several skipper butterfly species including the Dusted Skipper, Cobweb Skipper, Ottoe Skipper, Indian Skipper, Swarthy Skipper, and the Crossline Skipper. Other insects that feed on Little Bluestem include grasshoppers, Prairie Walkingsticks, the leaf-mining beetles, thrips, spittlebugs, and leafhoppers. The seeds of this grass are eaten by songbirds. Little bluestem provides necessary overwintering habitat and food sources for many insects and birds. Female bumble bee queens nest at the base of bunch grasses, like Little Bluestem, where they are protected until they emerge in the spring.

Planting ideas: a lovely grassy texture for the middle of a perennial border, to soften the edge of a garden pond, or wind it through a naturalistic planting.

Information sources: Perennial Plant Association and American Horticulture Society

After The Holidays Poinsettia Care

Posted by Hugh on December 26th, 2021

The gift of a poinsettia means you should enjoy the beauty over the next three months or more. Your poinsettia should be warmly wrapped to protect from chilling outdoor temperatures from the garden shop to your home or apartment.

If applicable, carefully unwrap the protective sleeve around your poinsettia to prevent injury to leaves and bracts and set it in a well-lighted winter that receives 4-6 hours of bright light daily. Keep the plant from cold or drafty windows.
Keep poinsettias away from warm radiators, air vents, and open doors. Poinsettias perform at their best in daylight temperatures of 60 to 70°F and night time temperatures around 55°F. High room temperatures will shorten plant life. When possible move the plant to a cooler room at night.
Check the soil (potting media) daily. Be sure to punch holes in pot foil so water will drain into a saucer or gravel tray. Water thoroughly when soil is dry and discard any excess water after 2-3 hours.
Mist the plant with room temperature tap water daily to raise the room humidity.
Start feeding your poinsettia within a month after purchase with any houseplant fertilizer. Or use a water soluble fertilizer such as Miracle-Gro™ or Peters™ @ one teaspoon per gallon of water. Continue to fertilize every 3-4 weeks through March.

True flowers in center surrounded by colorful bracts

With proper care, a poinsettia should continue to be colorful in your home to late February and into March. Snip off the dead or dying once colorful bracts.