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

Standout Ornamental Grasses Inflorescences

Posted by Hugh on November 6th, 2020

Ornamental grasses standout in the landscape most of the year.
These six ornamental grasses showoff spectacular seed heads (inflorescences) in late summer or fall. These grasses are also beautiful and effective landscape screens.

PAMPAS GRASS (Cortaderia selloana) – are seen planted at the beach, city parks or in your neighbor’s yard. The big feathery plumes sway in a passing breeze. Pampas grass varieties stand tall at 6-12 feet tall (plume included) and the dwarf pampas that reaches to a height of 4-5 feet tall (plume included). Cold hardiness is variable by cultivar.

Muhly Grass (Muhlenbergeri capillaris) – depending on variety the plumes of this native grass turns stunning pink (species) or white (cv. ‘White Cloud’).

MAIDEN GRASS (Miscanthus sinensis)– highly popular ornamental grass available in several varieties. Choose only varieties that produce mostly sterile inflorescences. Foliage is fine textured, with green to silver-green blades that develop golden-bronze tint after first frost. Striped leaf forms are also available. Recommended varieties include ‘Adagio’, ‘Bandwidth’, ‘My Fair Maiden’, ‘Morning Light’.

FEATHER REED GRASS (Calamagrostis x acutiflora) – compact 3-5 feet tall along with narrow growth form. Inflorescences ripen to tawny seed heads in late summer into fall and stand sturdily over the winter months. Several varieties are available, ‘Karl Foerster’ (green leaves), ‘Avalanche’ (yellow variegated leaves), and ‘Overdam’ (white variegated leaves) are very popular.

‘Karl Foerster’ Feather Reed Grass in Late Summer

FOUNTAIN GRASS (Pennisetum alopecuroides) (USDA zones 4-9)– their small size and bottlebrush type seed head are a perfect size for small to medium size gardens. Selections vary from dwarf varieties like ‘Little Bunny’ or ‘Hamlen’ growing 12-18 inches tall. P. orientale are less hardy and grow up to 3 feet tall (zones 6-9). P. purpureum ‘Prince’ and
P. setaceum ‘Fireworks’ are annual fountain grasses popular in most regions of the U.S. (zones 8-10). Some annual forms grow 6-8 feet tall in one growing season. Their upright stature, arching growth form, and fall seed heads standoff against either green, tan or rose colorful foliage.

SWITCHGRASS (Panicum virgatum) – become real showstoppers in fall with airy plumes atop the dark green late summer foliage. Cool fall temps causes foliage to turn bright yellow, some with dark red streaks. Most Panicum switchgrass grow from 3-5 feet high, including their fall floral heads. Popular forms include ‘Northwind’ and ‘Shenandoah’.

Ground Covers With Colorful Berries in Winter

Posted by Hugh on November 1st, 2020

Here are four ornamental ground covers that are laden with colorful berrries in the winter landscape. Two (partridgeberry and wintergreen) grow best in a partial shade woodland environment and two (coralberry and cotoneaster) prefer sunny environs. Berries offer tasty winter food for wildlife such as pheasant, grouse, squirrels and deer. Cut stems loaded with berries can be added to decorative indoor arrangements.

Cranberry cotoneaster (Cotoneaster apiculatus) is a low growing, widely branched deciduous shrub. It typically grows to 3 feet high with a spread of 4 – 6 feet. Tiny pink colored flowers appear in late spring and are visited by bees and other pollinators. In late summer red berries mature and persist into winter. The small glossy green spring-summer leaves (up to 3/4 inches long) turn attractive shades of purple, red and bronze in autumn. C. apiculata ‘Tom Thumb’ is a more compact form of cranberry cotoneaster. (zones 4-7).

Coralberry (Symphoricarpus orbiculatus), aka Indian currant, is a dense, suckering, native deciduousground cover found in Midwestern woodlands and fields (USDA hardiness zones 2-7). Coralberry spreads by runners to form impenetrable thickets in the wild. It mounds up 2-5 feet tall with arching stems. Clusters of white bell-shaped flowers (with a pink tinge) appear in summer. Flowers give way to colorful clusters of tiny coral-red berries (drupes) in autumn. Berries persist throughout the winter offering attractive color to a frosty landscape.

Wintergreen (Gaultheria procumbens) is a rhizomatous, creeping, woody, evergreen groundcover of the heath family found in the woodlands in Eastern North America. Erect stems clad with glossy, leathery, elliptic to oblong, dark green leaves (to 2 inches long) rise up from the rhizomes to 3-6 inches tall. Plants gradually forms an attractive ground cover over time. Waxy, nodding, bell-shaped, white flowers (3/8 inch long) open in the leaf axils in early summer (June-July). Flowers give way to edible bright red berries (3/8 inch diameter) that persist through winter. Fall leaves take on shades of purple. Leaves and fruit emit a wintergreen aroma. (zones 3-8).

Partridgeberry (Mitchella repens) is grown for its evergreen foliage, spring flowers and winter berries. This native low-growing groundcover can be found in acidic soils in moist woodlands and on stream banks in the Eastern and Midwest U.S. In the spring woodlands, small four-petaled white tubular flowers are arranged in pairs above the foliage. Bright scarlet red berries follow in late summer, fall and winter. (USDA hardiness zones 4–8).

Fire Chief™ Arborvitae

Posted by Hugh on October 26th, 2020

Fire Chief™ Arborvitae (Thuja occidentalis ‘Congabe’) is a compact, globe-shaped evergreen that grows 3-5 foot high and wide (in 10 years) (USDA hardiness zones 5-8). It is at its best in full to partial sunlight. Its soft scale-like foliage changes color seasonally. New spring growth emerges orangey-red, turns bright green in summer, and develops a russet-red blush in fall and winter. When planted on a sheltered or shady site, the leaves retain a bright green color year-round.

Its scaly leaves resist burning from harsh summer sun and the frigid winds of winter better than many globe arborvitaes. Branches are flexible and rarely break under a snow load. This super hardy evergreen thrives in containers through the coldest Tennessee winter. Its compact size makes this evergreen shrub an ideal choice for small gardens.

One year after planting, Fire Chief is moderately drought tolerant and requires very little maintenance. Disease and insect problems are rare, although deer may occasionally browse on the foliage.

At local garden centers Fire Chief™ is available as a container-grown shrub from spring thru early fall. This outstanding cultivar performs well in an average well-drained, moderately acidic soil. Before planting enrich the soil with compost and mulch. It is rated as moderately drought tolerant after one year.

Spring pruning is rarely needed except to remove a broken branch or for shaping. Annually feed the shrub with either 10-10-10 or an equivalent granular fertilizer in late winter.

Fire Chief™ arborvitae is grown for its compact globe conifer seasonal accent foliage shrub in a container or a garden setting.

Deciduous Holly For The Fall/Winter Landscape

Posted by Hugh on October 22nd, 2020

While deciduous hollies (Ilex spp.) are well known among home gardeners, surprisingly few plant them (USDA hardiness zones 3-9 variable by species). In the fall, their branches and twigs are covered in bright red berries. Orange and yellow berried varieties are additional choices. Birds love them, too.

Deciduous hollies do not have prickly leaves like evergreen hollies. Their foliage is soft and non-spiny. Two prominent native species — winterberry (Ilex verticillata) and possumhaw (Ilex decidua) and Japanese winterberry (Ilex serrata) — are planted. Numerous hybrid crosses are also available.

Plant deciduous hollies from spring into early fall in a full to part day sun location (five or more hours best). Deciduous hollies prefer moist, acidic soils, and don’t mind wet ground. Possumhaw grow tall and wide in moderately alkaline soil. Most important with hollies is that female cultivars must be matched to one or more specific male clones (such as ‘Raritan Chief’ (possumhaw), ‘Jim Dandy’ or ‘Southern Gentlemen’ to winterberry hollies, and Apollo’ to ‘Sparkleberry’ holly for best pollination.

Few gardeners take notice of the tiny white flowers in spring. Insect pollinators do frequent the blooms. Bloom varies with the species group. Cultivar heights vary from 2 to 18 feet high and 4 to 10 feet wide. Give individual plants plenty of room.

Two-year established shrubs are moderately drought tolerant, but produce greater numbers of berries if summer rainfall is adequate. Fertilize in March or April with an acidic organic slow-release fertilizer such as Holly-tone® or Osmocote®. No serious insect or disease problems trouble deciduous hollies.

Clip off berry-covered twigs and branches in fall and winter to bring indoors and arrange in tall vases; no need to add water as cut stems will last quite awhile. When shrubs grow too large, cut them back in early spring by one-third or more, even to the ground. Renewal pruned deciduous hollies will quickly emerge from suckers.

Hedges of deciduous hollies attract all kinds of birds to your property and offer nesting and winter protection for our feathered friends. For best accent plant them against a background of needled evergreens, the red winter berries will stand out.

EXTRA info: Orange-red berried (Ilex verticillata ‘Aurantiaca’) and (I. v. ‘Afterglow’) grows 6 to 8 feet tall, and fruits fade to orange-yellow. Compact cultivar ‘Red Sprite’ stays about 5 feet tall and both are pollinated with ‘Jim Dandy’.

Claim Jumper™ Katsura Tree

Posted by Hugh on October 16th, 2020

B&B Claim Jumper trees (Photo credit: Heritage Nursery, WA)

In American gardens Katsura tree (Cercidiphyllum japonicum) is a fine landscape tree that is becoming more popular. This small – medium – large tree (height depending on cultivar) offers four-seasons of interest.

Katsura tree is indigenous to Japan and China where it can mature into an incredible 50-70 feet tall USDA hardiness zones 4-8). Numerous green leaf forms, including weeping cultivars, are available. Its tiny flowers are dioecious tree (male and female flowers on separate trees) and mostly inconspicuous.

One standout cultivar, Claim Jumper™ katsura, offers a golden or chartreuse look. It is a fine 25-30 feet (8-10 m) tree. The leaves of this small Katsura emerge with a pinkish tinge, and unfurl with a soft golden-yellow color. By mid-summer, leaves in the shade may turn light green while those in sun are pale yellow, giving the tree a two-toned effect. Leaf shape is cordate (heart-shape).

Fast growing when young, a tree averages 1.5 to 2 feet per year or to 20 feet tall in 10-15 years. That’s about the growth rate of a sugar or red maple. Claim Jumper holds this chartreuse leaf color through most of summer. Young trees maintain an upright branching form, almost into middle age.

Katsura trees should be planted a moist well-drained soil and in full sun to part-shade, depending on the region of the U.S. Newly planted 1-2 year old trees are particularly prone to leaf scorch. During its 2-3 years after planting, a young tree is susceptible to long dry spells and should be irrigated, particularly where summers are very hot. Mulch and feed the tree with a slow release fertilizer in early spring.

In warmer Southern climes, Claim Jumper should be protected from the hot afternoon sun from buildings or larger trees on the west or south exposure sides. In autumn, about the time the golden leaves are starting to drop, you will smell a sweet fragrance like cotton candy in the air.

Katsura is rarely troubled by serious pests or disease problems. Many cultivars are sold in limited numbers by full-service garden centers or by rare plant specialty nurseries on-line.

Shumard Oak

Posted by Hugh on October 11th, 2020

Shumard Oak (Quercus shumardii) is stately landscape tree in the red or black oak group (USDA hardiness zones 5-8). The species is native to moist bottomlands and slopes of the southeastern U.S.

Typically, Shumard grows at a moderately fast rate to a height of 40-60 feet (30-40 feet wide) in the landscape. It has a pyramidal or upright-branching with an open canopy and sturdy spreading branches. As the tree ages, it develops a broad open crown.

The 6-8 inch long seasonal leaves are glossy, dark green. Shumard oak leaves resemble those of scarlet oak (Q. coccinea), distinguished by 7-9 deeply cut lobes and are bristle-tipped. Leaves turn brownish red by late autumn.

This medium to large shade tree prefers a spacious sunny location. Insignificant flowers (separate male and female catkins) appear in early spring before the leaves start to emerge. Numerous 1-inch long acorns (take 2 years to mature) provide food for all kinds of wildlife including numerous birds, including woodpeckers, as well as wild turkeys, and squirrels, deer, et al.

Shumard oaks are utilized as shade trees in lawns and street trees. It grows well in wide variety of soils. It is widely adapted to drier limestone soils and high pH levels. However, chlorosis (yellowing of the foliage) sometimes occur in calcareous soils (low in acidicity). Most oaks, including Shumard, demonstrate good drought tolerance within a year or two after planting.

Shumard oaks are durable long-lived trees, but are potentially troubled by a large number of potential diseases and insect pests, including anthracnose, canker, leaf spot, rust, blight, galls, caterpillars, borers, leaf miners, oak lace bug and oak mite.

As a rule, shumard oaks are generally long-lived when properly planted and cared for. Large nursery grown trees may be difficult to transplant and are best moved in late winter or very early spring.

Deciduous Trees With Yellow Fall Leaf Color

Posted by Hugh on October 6th, 2020

While there are numerous trees that offer wonderful yellow fall foliage, some make extraordinary specimens in residential and park landscapes. Enjoy the beautiful yellow and gold tones on a crisp fall day. Caveat: the quality of fall color may vary from year to year.

Big-leaf maple (Acer macrophyllum) – this West Coast Native grows 60-75 feet tall tree with huge leaves that turn a rich shade of yellow in autumn, many times with a hint of orange. Zone 5-9.

Ohio buckeye (Aesculus glabra) – small- to medium-sized tree produces yellow fall foliage, but the leaves sometimes are red or orange, depending on weather conditions. Zones 3-7.

Serviceberry (Amelanchier x grandiflora) – small, showy spring flowering native with variable yellow to orange-red fall color. Zones 4-9

Pignut hickory (C.arya glabra) –this tap-rooted large 50-60 feet tall woodland tree in the eastern and Midwest U.S. exhibits above average golden yellow-brown fall color. Zones 4-8.

Shagbark hickory (Carya ovata) –shagbark hickory’s colorful foliage that turns from yellow to brown as autumn progresses; known for its shaggy bark and flavorful nuts. Zones 4-8.

Katsura tree (Cerciphyllum japonicum) – large 50-60 feet tall, rounded tree that produces purple, heart-shaped leaves in spring with apricot-yellow fall foliage. Zones 5-8.

Eastern redbud (Cercis canadensis) – native spring flowering famous favored for its rose-purple flowers and attractive, greenish-yellow fall foliage. Zones 4-8

Green ash (Fraxinus pensylvania) – pinnately compound foliage turns yellow in fall, with quality of the fall color often varying considerably from year to year. (Zones 3-9).

Ginkgo (Ginkgo biloba) – aka maidenhair tree, develops an attractive, fan-shaped foliage that turns bright yellow in autumn. Zones 3-8.

Larch (Larix spp.) – Available in a range of sizes and forms, larchis a deciduous evergreen tree that grows in cold, mountainous regions. Fall foliage is a shade of brilliant, golden-yellow. Zones 2-6.

Tulip poplar (Liriodendron tulipifera) – aka yellow poplar, this huge, tall tree is actually a member of the magnolia family. It is one of the prettiest, most majestic trees with yellow fall leaves. Zones 4-9.

Persian ironwood (Parrotia persica) – small to medium tree that produces a range of sunset colors, including variable orange, red and yellow fall foliage. Zones 4-8.

False larch (Pseudolarix amabilis) – this deciduous conifer from China is rarely seen in U.S. landscape; grows 30-60 feet tall and never fails to provide a wow! golden to bronze leaf color in October, often lasting 2+ weeks. (Zones 4-7).

False Larch (*Pseudolarix amabili*s) at the NC Arboretum in Asheville, NC

Fall Clean Up Of Garden Beds

Posted by Hugh on October 1st, 2020

Cleaning up vegetable and flower beds requires some thought. Most gardeners desire to get a start on next spring’s clean up in the fall. They may rototill garden beds in fall, particularly if soils are too moist to work in early spring. Turning the soil also kills lots of weeds, including winter weeds which have already already germinated and have been growing through the winter months.

Cut back almost all plant debris: spent flowers, stalks, anything dead. Tender perennials such as pampas grass, lavender, and rosemary should not be pruned back until spring. However, bearded irises benefit being cutback in the fall as the larvae of iris borers make their winter home in the garden debris.

In early fall, use Preen® weed preventer to suppress cool season weeds from sprouting in garden soil. Weeds like chickweed and henbit germinate in the fall, and put on a growth explosion during the mild days of February and March.

Lay a thin layer of mulch over the perennial beds, just an inch or so, to protect any flower bulbs, perennial roots like calla lilies, and prevent soil loss on slopes and tempermental perennials like angel trumpets (Brugmansia), cannas, and elephant ears

Once the garden bed is cleaned up and free of debris, fall is a good time to test your garden soil to prepare for a great growing season come spring. Every 4-5 years, have your soil analyzed to check the pH level and nutrient content. In the spring you will know how much fertilizer to add. Your local Extension Office will offer this soil testing service for a fee.

Based on the soil report, if the soil pH is too acidic, add limestone; too high pH (alkaline), add elemental sulfur or gypsum to increase soil acidity. Independent garden centers and farm supply stores are good places to buy limestone or sulfur to apply in the fall. Winter precipitation and cold temperatures will break down lime and sulfur. Soil pH levels should be adjusted by the time spring arrives

Lastly, take a few minutes in the fall to write down your garden successes and failures over the past growing season. This will help you to plan next year’s garden. New flower or vegetable catalogs will be arriving to the mail.

EXTRA: If you plan to feed birds and other wildlife in winter, do not cut back the seed heads of certain perennials and annuals such as: coneflowers (Echinacea), blackeye Susans (Rudbeckia), globe amaranths (Gomphrena) and zinnias.

Tips On Growing Fern Leaf Peony

Posted by Hugh on September 26th, 2020

Fernleaf peony (*Paeonia tenuifolia*i) -photo courtesy of Hollingsworth Peony Farm

Fernleaf peony (Paeonia tenuifolia), sometimes called “fennel peony”, is recognized principally for its finely dissected foliage. When properly sited and cared for, it is a low maintenance perennial. This uniquely different peony is native in parts of Eastern Europe (USDA hardiness zones 4 – 8).

Peonies perform best in well-drained, evenly moist, compost rich soil with a pH near neutral. Plants usually fail in clay soil unless it has been generously amended with compost. Plants become drought-tolerant after one year in the garden. Site fern leaf peonies in full to partial sunlight and in average to moist soil that is well-drained. Never allowed plants to dry out and avoid dry windy sites.

Fernleaf peonies are treasured by peony connoisseurs and rare plant collectors. Leaves are susceptible to leaf spot and mildew diseases. Do not overhead irrigate fern leaf types to prevent foliar disease outbreaks. Deer generally leave peonies alone. They’re tolerant of urban air pollution. Plants are propagated by division.

At the start plant growth may be slow, but fernleaf peonies are long-lived, some over 25 years when properly sited and annually cared for. Set the thick fleshy roots below the soil with the buds (eyes) 1.5 to 2 inches below soil level. Plants barely stand 18 to 24 inches tall and 24 inches wide. The 2 1/2- to 3-inch, bright red flowers bloom in late summer have very short stems and they appear to sit directly on the foliage.

In southern climes (GA, FL, AL, MS), protect their delicate finely cut foliage from drying afternoon sun and from high winds. Floral stalks may be weak if planted in excessively rich soil or too much shade. Some may require caging or staking soon after shoots emerge in spring. Fernleaf peonies tend to go dormant in mid-summer.

Water fernleaf peonies often enough to keep the soil moderately moist. Feed fern leaf peonies with a mixture of bone meal and either compost or well-rotted manure in early fall before the foliage fades. If you opt to use a commercial fertilizer, choose one with a lower percentage of nitrogen (N) than phosphorous (P), and potassium (K) or a 1:2:1 ratio. High levels of nitrogen lead to fewer flowers.

Double Fernleaf (‘Rubra Plena’) peony features bold lightly-scented dark red flowers at the ends of the stems from late spring to early summer. Flowers are suitable for cutting.

Fernleaf peonies are more expensive that most herbaceous types. Plants are available from online nurseries and specialty peony nurseries.

Fall Color Of Ornamental Grasses

Posted by Hugh on September 21st, 2020

Muhly Grass (Muhlenbergeri capillaris) grows 3-4 feet with blemish-free green foliage all summer long. By early fall, its bright colored floral seed heads (inflorescenses) are showing up, which gives Muhly its decorative look. ‘Pink Muhly’ tends to grow floppy and struts pink-hued inflorescenses that shimmer in a breeze. ‘White Cloud’ is a white flowering form of muhly that stands more upright. (USDA Hardiness Zones 7 – 11).

Many switch grass (Panicum virgatum) develop great fall leaf color. In summer, the leaf blades of some switch grass varieties develop showy red-stained tips. ‘Shenandoah’ blades turn rich black-burgundy; ‘Northwind’ – bright gold streaked fall foliage; ‘Cheyenne Sky’ – dense, blue-green blades turn wine red in early summer and purple inflorescence appear in late summer (zones 5-9).

Big bluestem (Andropogon ternarius) varies across its natural range, growing as high as 5 feet tall in some areas. NC selection ‘Black Mountain’ stays 3 feet or under, and grows more compact than the species. Flowering stems emerge bluish-green and develop reddish hues later in summer. The inflorescences are composed of spikelets covered in silvery, white hairs.(zones 6-9)

Fountain grasses (Pennisetum spp.) represents a huge selection of both annual (P. setaceum) or perennial (P. alopecuroides) fountain grasses. Among the perennial varieties are: 1. ‘Rubrum’ holds its red color all season; 2. ‘Moudry’ has spring-summer green foliage that turns golden yellow foliage and burgundy red foxtail plumes in fall; 3. ‘Fireworks’ (annual) is highly colorful through most of the season.

Feather Reed Grass (Calamagrostis x acutiflora) is a cool season plant that is one of the first ornamental grasses to shoot up in spring. It also is one of the first to go to seed. ‘Stricta’ and ‘Karl Foerster’ have reddish seed pods and ‘Overdam’ turns golden. (USDA Hardiness Zones 4 – 9)

Prairie Dropseed (Sporobolus heterolepis) has thin, airy leaves that create a weeping habit. In cool fall weather and ample soil moisture, the leaf blades turn almost pumpkin orange (Zones 3 – 9).