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

Indian Pinks

Posted by Hugh on June 7th, 2024

Indian Pinks (Spigelia marilandica) is a strikingly beautiful native wildflower throughout central and southeastern U.S. It is sometimes called “woodland pinkroot”. This perennial grows well in many parts of the U.S. (Zones (5b-9). Plants emerge in mid-spring. Sometime in June, depending on locality, their bright red tubular flowers flare open, crowned by five sharply pointed pale yellow reflexed lobes. By the 4^th of July flowers will provide floral fireworks in your garden.

Indian pinks prosper around a rich moist open woodlands or shade garden. They grow equally well in mixed containers. Plant in a well-drained, mildly acidic soil that is generously amended with compost or humus. A partially sunny site in full morning to dappled sunlight is ideal. Irrigate plantings during summer dry periods and avoid wet soggy soils.

In older plantings vigorous plants will grow 2 – 2.5 feet tall. Leaves are arranged opposite on the stem, attached directly to the main stem (no petioles), as well as an entire (toothless) margin. Plants stand erect and are rarely branched.

New plantings of Indian pink often start off slowly, taking 2-3 years to reach maximum flowering. Create a dazzling display by setting five or more plants en masse. Over the years in good humus-rich soil, Indian pinks often naturalize and look stunning. Flowering time may be extended over several months by swift removal of the old spent flowers (deadheading).

The brightly colored flowers attract numerous pollinating insects and provides food for hummingbirds. No disease and pest problems cause Indian pink any troubles.

The popularity of Indian pinks continues to increase. In recent years, the U.S. native plant industry have been adding new clones of Indian pinks to their catalogs and many more garden centers, not box stores, are selling them. Tissue culture labs are also producing them. Relatively new in stores is a vegetatively propagated clone ‘Little Redhead’ which demonstrates high vigor and plant uniformity. (24-28 inches high and 20-24 inches wide).

Another Indian Pinks selection, ‘Ragin Cajin’, has orange red flowers on a rounded plant form (20-24 inches high and wide). This selection from Plant Delights Nursery in Raleigh is highly floriferous and performs well in either sun or shade. (20-24 inches high and wide).

Mini-Oakleaf Hydrangeas

Posted by Hugh on May 26th, 2024

Oakleaf hydrangea (Hydrangea quercifolia) is a U.S. native and it offers four seasons of landscape beauty. (USDA hardiness zones 5-9). Typically, oakleafs grow 10-12 feet tall deciduous shrubs that are broad-rounded, suckering, and multi-stemmed. In the wild, if left unpruned, shrubs reach over 20 feet in height and spread.

I have selected five compact growers in the 3-6 feet range. They’re an ideal size for large 15+ gallon containers and planting in small gardens. The large leaves mimic those of oak trees. Cone-shaped white flowers are cone-shaped and comprised of showy sterile flowers that protect the mass of fertile flowers beneath.

Oakleafs are easily grown in humus-rich, moist, well-drained soils in full sun to part shade. Provide adequate shade in the southern U.S. zones so that plants are never over-stressed in droughty soils. Annual summer mulching in pine needle or ground / bark-based aids retain soil moisture and weed maanagement.

Bloom occurs on old wood (last year’s growth). Pruning, if needed, should be done immediately after flowering in early August to rein in shrub size, despite removal of many spent flowers that still look attractive. An added attribute is that inner branch wood and stems exfoliate to reveal a rich brown inner wood.

Dwarf (Compact-growing) Cultivars:

‘Little Honey’ is a petite grower (3-4 feet tall and 4-5 feet wide) with snow-white cone-shaped flowers. Flowers are secondary to its glorious chartreuse foliage. Shrub grows best in full sun in the north and in partial sun to partial shade in the mid-South. The aging flowers turn crimson at the start of autumn.

‘Pee Wee’ grows 4 feet high and 3 feet wide white spring flowers that fade to pink in the fall. Its oak-leaf like foliage stays deep green through summer and turns bright red in autumn.

‘Sike’s Dwarf’ has a dwarf mound habit that matures 2-3 feet in height and 3-4 feet in width. Elongated, conical white, mostly sterile flower panicles, each 3-4 inches long, gradually fade to light pink and eventually brown in fall. Deep green 3-5 inch long leaves turn autumnal shades of bronze, maroon and purple.

‘Ruby Slippers’ is a U.S. National Arboretum introduction that grows 3 to 4 feet tall and slightly greater in spread. ‘Pee Wee’ is one of its parents. Large flower clusters emerge white, age to light pink and mature to ruby red. Its leaves turn deep mahogany red in fall.

‘Munchkin’, another National Arboretum release, is a compact grower that matures to 3 to 4 ½ feet tall and wide with a rounded shrub form and dark green leaves that turn deep burgundy in fall. Large clusters of white flowers stand upright age to pink.

‘Gatsby Girl’ (photo from PW. thank you!)

Gatsby Gal® is a semi-dwarf oakleaf hydrangea from Proven Winners (PW) that grows 5- 7 feet tall and wide. Its green, oak-shaped foliage and large fragrant blooms in summer finishes with an outstanding fall color.

No serious insect or disease issues trouble oakleaf hydrangeas. Some susceptibility to leaf blight and powdery mildew. Aphids and spider mites are occasional visitors.

Attention Blog Readers: Interested in “larger growing oakleaf hydrangeas”? Look for a blog titled as such.

MT. Cuba Evaluates BlueStars (Amsonia)

Posted by Hugh on May 21st, 2024

New Amsonia ‘Starstruck’ Planting in Parking Lot of Mt Cuba Center

MT. Cuba Center is located near Hockessin Delaware, near Wilmington (USDA hardiness zone 7a.). It has recently published a new trial report on bluestars (Amsonia spp.) for the mid-Atlantic region. BlueStars are a genus of popular, long-lived herbaceous perennials. Most are native to the U.S. and Mexico in addition to one Asian species (A. elliptica) and (A. orientalis) in Greece and Turkey.

Mt. Cuba Center conducted over 10 years that evaluated several varieties, cultivars, and hybrids of three U.S. native species – A. ciliata, A. hubrichtii, and A. tabernaemontana. The trial focused on garden performance and ornamental qualities. It evaluated 20 different Amsonia varieties.

Amsonia species and cultivars vary in overall size and ornamental qualities such as foliage texture and bloom time, but all provide multiple seasons of ornamental interest. Sprays of blue flowers arrive in mid-spring followed by blemish-free summer foliage. Many varieties close the year with outstanding gold or orange fall color, especially when grown in full sun.

Cold hardiness will vary with species. Most bluestars are hardy in USDA hardiness zones 3-11. In harsh northerly areas, bluestars may be overwintered by covering them in a heavy frost blanket, or overwinter container plants in an unheated garage that stays just above freezing.

The Amsonia trial was grown in part-to-full sun in “average” soil, best described as clay-loam with a pH near 6.5. Throughout the trial, plants were given minimal care. Supplemental water was provided only during the first year after planting to encourage establishment.

BlueStars support early-season pollinators including native bees and hummingbirds and are the host plant for several species of butterflies and moths. Amsonias are botanical members of the Apocynaceae family, which includes milkweed (Asclepias); plant stems produce a milky sap that discourages browsing by deer and other mammals.

Most BlueStar varieties grow about 2-3 feet tall, and 2-3 feet wide. small, tidy, shrub-like clumps. Leaves are 3-4 inches, narrow and lance-shaped, with a pronounced mid-rib. Species size will depend on the variety grown and garden conditions.

*Amsonia ciliata tenuifolium* (white form)

Garden notes: Amsonia species prefer from full sun to part shade and a moist soil with a pH between 6.2-7.0 but adapt to most soils. They do not like prolonged dry conditions but once established. BlueStar plants can handle brief periods of drought. BlueStars thrive in a hot and humid climate.

Bluestar requires very little maintenance. Bloom clusters can get floppy when heavy with flowers and the seed pods that follow. To prevent this, either stake them with a hoop or trim them back by one third after flowering. Trimming will mean losing the attractive seed pods.

BlueStar can be grown from seeds harvested when the pods dry. You can start seeds in the fall or overwinter them in a cold frame or protected area, then transplant in the spring. Simply cover them lightly with soil and keep the soil moist until plants germinate.

Minor chlorosis and rust symptoms occur in high pH above 7.0. Otherwise, BlueStar plants are virtually problem free, and pests or diseases regularly bother them.

In late winter or early spring, cutback (cleanup) the previous year’s foliage. BlueStar stems are hollow, leaving 12 –18 inches of stem and provide a habitat for native bees.

Diseases were infrequently observed in this trial, and aside from the plants were virtually pest and disease free. BlueStar may be started from seed or purchase plants from nurseries and garden centers.

*A. tabernaemontana* ‘Montana’ – deeper blue flower & slightly wider leaves

Successful Gaura Growing Tips

Posted by Hugh on May 3rd, 2024

*Oenothera* lindheimeri ‘Whirling Butterflies’

Gaura (Oenothera lindheimeri) is a low-maintenance perennial native to the southern U.S. (Zones 5-9) and is a durable plant for gardeners. Its waving wands are dotted with dozens of whitish to pinkish flowers don’t stop blooming until summer temps climb above the 90°F range. Gaura is often called “whirling butterflies” because the flowers appear to dance in the breeze.

Gaura blooms all summer long producing graceful wands of nectar-rich white, pink, or bi-colored flowers that butterflies love. The deer-resistant plants grow 2-3 feet tall. Although whitish flowering forms have small, mostly non-distinctive green leaves, the foliage develops reddish tones in the dark pink flowering varieties.

Gauras are not long-lived perennials; wet winter soil will kill these drought-tolerant natives. Thus, site selection and ground prep are very important components in growing gauras. Plants have a long deep taproot and can be difficult to transplant. It is heat and drought tolerant and can handle high humidity with ease. It’s at its best in full sun but tolerates some afternoon shade in warm Southern climes. Excellent drainage is the key to success. Amend the soil with a mix of compost and gritty sand (not beach sand) or in raised beds.

Plant 3-5 gaura plants for maximum impact and space them at least 12-15 inches apart. Dwarf varieties are also an excellent container plant. Irrigate gaura sparingly to encourage this taproot plant to dig deep. Generally, gaura thrives in poor lean soil and does not require fertilizing. Too much fertilizer can make plant(s) floppy.

Gaura (Wandflower) Varieties- Four beautiful varieties include:

‘Corrie’s Gold’: Flowers are white tinged with pink and gold variegated foliage.
‘Passionate Rainbow’: pink flower wands and pink-edged foliage.
‘Siskiyou Pink’: showy rose-pink flowers on its notably wispy stems.
‘Sparkle White’: dainty white flowers are tinged with pink.

Overall, gauras may be affected by certain pests like aphids, whitefly and flea beetles. Root rot may occur in heavy and/or poorly drained soils. Rust and powdery mildew may also occur. Applications of insecticidal soap should resolve most pest issues. Gauras are also deer and rabbit resistant.

Gaura plants may flop over in the garden, and staking may be an option. Rigid, upright flowers like hyssop (Agastache), ‘Autumn Joy’ sedum, globe thistle (Echinops), or blazing star (Liatris) have similar growing conditions and blooming periods in a dry garden. Flowers invite pollinators by the score. Dwarf varieties make also excellent container plants.

Rethink Before Planting These Five Groundcovers

Posted by Hugh on April 26th, 2024

Initially, these 5 groundcovers were alluringly beautiful. But, over time, each grow very aggressively and become a major chore to restrained in the garden. Several states have declared one or more species as invasive and ban them for sale and interstate transportation.

English Ivy under tree growing up trunk and on ground

Purple Wintercreeper (Euonymus fortunei ‘Coloratus’, also known as Euonymus fortunei var. radicans, Euonymus radicans, Euonymus japonicus var. coloratus) and others. Purple Wintercreeper, is a very well-known ground cover. This trailing vine grows 12-18 inches tall and 24-36 inches in spread. The two-inch long leaves are glossy, ovate to elliptic, dark green (above) and purplish-red beneath). Leaves turn purplish red in fall and winter. Euonymus prefers moist, well-drained soil conditions in partial shade. (Zones 5 to 9).
Bishop’s Weed, Goutweed (Aegopodium podagraria variegatum) is an aggressive plant that forms dense patches via long, white, and spreading rhizomes. Goutweed grows in many areas of the U.S. and becomes a high maintenance weed. Growth-wise, the cultivar ‘Variegatum’ has basal light green foliage with creamy white margins. While rated as less aggressive than the species, plants may revert back to the green leaves with greater vigor. Foliage of variegated goutweed will burn in full sun. (Zones 3-10).
Evening primrose (Oenothera speciosa), aka Mexican primrose or Showy Ladies, blooms in the evening hours. Most garden shops do not sell it and have become a pass-a long between other green hobbiests. Flowers usually remain open thru late morning. The 1.5 – 2-inch-long seed capsules follow. By late summer the plant(s) have disappeared from their garden spots. Some seeds and underground runners return the next spring. (Zones 4-9). NOTE- As a North American native species, does not qualify as an invasive plant.
English Ivy (Hedera helix) is a high-climbing, evergreen vine available in many varieties at garden centers. English ivy is a common house plant. It has become an invasive garden plant in many areas of the U.S. Most varieties are aggressive groundcovers that grow in a wide range of sun or shade conditions. Some are meek and don’t attempt to take over. Ivy vines invade and spread into native forests and smothers tall trees and low growing native plants on the forest floor. Similarly, they rapidly cover trellises, walls, fences, trees, or any structure that they encounter. (Zones 4-13)
Creeping myrtle (Vinca minor), aka common periwinkle, is an aggressive low maintenance ground cover that excels in shady landscape areas. This low-spreading plant. grows vigorously in woodsy areas and into shady lawns. (Zones 4-9). Equally invasive is its large leaf cousin, Vinca major, but not as winter hardy in zones 7-9.

The most effective way to eliminate these aggressive groundcovers is to cut plants to the ground after they have fully leaved out in the spring, and next blanket the ground with black plastic or heavy cardboard. This will prevent photosynthesizing, essentially depleting their carbohydrate reserves. An alternative method is to overspray young foliage or cut stems/vines containing the ingredient glyphosate (Roundup™ and other labels) or Triclopyr (Garlon™).

Sweetbay Magnolia Cultivars

Posted by Hugh on April 19th, 2024

Sweetbay magnolia (Magnolia virginiana) is a U.S. native tree that is finally catching on with landscape designers. Sweetbay often grows 20-30 feet tall and 15-20 feet wide as a large shrub or multi-stemmed small tree. Discovering a 50-60 feet sweetbay near by a lake or pond is not unusual to find (USDA hardiness zones 5-9).

Sweetbay blooms from mid-May through June with occasional flowers from May into July. The flower petals of magnolias are called “tepals” and sweet bay flowers consist of 8-10 tepals. The creamy-white blooms are 3-4 inches across and last 3-4 days. Numbers of open flowers are rarely abundant at any one time. On occasion their sweet lemony fragrance becomes quite evident in the late spring garden.

The glossy light-green leathery leaves are 4-5 inches long. A slight fluttering breeze exposes the silvery underside of the leaves. Foliage is reliably evergreen in USDA hardiness 7-9 and semi-evergreen in zone 6. ‘Green Shadow’ and ‘Moonglow’ are leading cultivars that exhibit slightly larger flowers, darker green leaves, and better winter hardiness.

In early fall green cone-like seed capsules burst open to expose bright orange to red seeds within. Seeds may be collected in late September and stratified (refrigerated) in moist sand over 3 months @ 32 to 41°F; or seeds may be sown directly in the garden. Seedlings emerge from the soil the following June.

Unlike most magnolia species, sweet bay flourishes in moist soils, including those that are flooded for short periods. This species tolerates wet, swampy, and boggy soils whereas most other magnolias abhor “wetfeet”. ‘Australis’ forma are more reliably evergreen than the species. It prefers a humus-rich, acidic soil; summer leaves may turn chlorotic (yellow) in iron deficient alkaline soils. Disease and pest problems are rare.

Pale green glossy foliage and fall fruiting

Sweetbay is well-suited for a small urban garden near a patio or deck. Cut foliage is often included in holiday wreaths and garlands, and in table and floral arrangements.

Choose from dozens of sweetbay magnolia cultivars, including these 8 popular forms. Some cultivars are listed under two names. Verify winter hardiness ratings before purchasing; some will defoliate following a harsh winter. Some are winter hardy to zone 7, while a few are winter hardy in zone 5 and retain their foliage through winter:

‘Emerald Tower’ grows to about 20 feet, with glossy green foliage along with exceptional zone 4 hardiness.
‘Green Shadow’ (M. virginiana. var. australis), also named ‘Greenbay’, was introduced by Tennessee Nurseryman Don Shadow from seedlings collected by Dr. Joe McDaniel.
‘Moonglow’ (‘Jim Wilson’) grows 15-35 feet tall and 10-20 feet wide.
‘Henry Hicks’ is an unusually large 35-40 feet tall cultivar exhibiting a more columnar growth habit and is rated evergreen in zone 5.
‘Keltyk’ has smaller leaves, a more compact habit, and is evergreen in zones 7-10; utilize as a 25 feet patio tree; creamy white flowers are highly fragrant on a summer evening.
‘Santa Rosa’ has the largest leaves of any cultivar and has a spreading habit that grows to 25 feet tall and 20 feet wide; best in zones 6 – 9.
‘Northern Belle’ grows 20-25 feet height and 15 feet width; large white blossoms that emit a vanilla fragrance from May to July.
M. (australis) ‘Mardigras’ (‘Mattie May Smith’) has unique variegated foliage (yellow margin/green center leaves); 15 feet shrub or tree; semi-evergreen foliage; Zones 5 -7 winter hardy.

Chinese Fringetree

Posted by Hugh on April 7th, 2024

Gardeners are waking up to the tough as nails Chinese fringetree (Chionanthus retusus). (USDA hardiness zones 5-9). It has gorgeous foliage, showy snow-white flowers in the spring, and exfoliating bark. Native to Korea, China, and Japan, this low maintenance multi-stemmed large shrub or small deciduous tree is becoming easier to purchase at U.S. garden centers and online nurseries.

Flowers often appear about 1-2 weeks before U.S. native species C. virginicus. This low maintenance beautiful tree likes an average, medium moist, fertile, acidic soils and in full sun to part shade. Best flowering occurs in full sun. It seldom needs pruning. Tolerant of air pollution and adapts well to urban settings, it abhors long summer dry periods.

Chinese fringetree ranges in height from 20 – 30 feet with lovely textured bark which is also exfoliating as the tree ages. If planted in the South, add another 10 feet in height. Set the tree in full sun or partial shade. The lustrous, leathery oval-shaped leaves and wispy fragrant white flowers are its key pluses. Some gardeners report it is a biennial bloomer, blooming heavier in alternate years, one year ON and next year OFF (far fewer flowers).

Both our native and Chinese fringetrees are underplanted. Propagation from seeds and cuttings is slow resulting in higher production costs. Mulch the tree with 2-3 inches of mulch and replenishing it every year to improve soil quality. Spread 9-10- month slow-release formulated fertilizer in the fall/early winter.

Fringetrees are primarily dioecious (separate male and female flowers). Flowers are slightly more showy on male trees. Female trees flowers, if pollinated and fertilized, will produce clusters of olive-like fruits (each to ½ inches long) which ripen to a dark bluish black in late summer/fall and are a good food source for birds and wildlife. Fall leaf color is an average yellow. When a young tree, bark is light brown exfoliating and strikingly furrowed as it ages.

No serious insect or disease problems. Some susceptibility to mites, scale and borers. Watch for leaf spots, canker and powdery mildew. Plants sold in commerce are not labelled “male” or “female”. Fringetrees may be damage by fruit feeding deer.

Cultivars / Varieties:

China Snow – multi-stemmed, slightly smaller version @20-25 feet tall and wide and an excellent alternative in urban settings

Tokyo Tower – 12 to 15 feet tall and 4 to 6 feet wide with a narrow upright branching “stovepipe” appearance as well as a tan and gold exfoliating bark; good candidate as an urban street tree.

Lacebark Pine – A Year-round Treasure

Posted by Hugh on April 1st, 2024

Native to China, lacebark pine (Pinus bungeana) is an excellent, low-maintenance evergreen treasure. Winter-hardy in USDA hardiness zones 4-8, this specimen pine struggles in the summer heat and humidity of the Southern U.S. Best specmens are found growing in arboretums and botanical gardens north of zone 8. This 3-needle pine offers 4-seasons of ornamental interest. During a snowy winter, within 12-15 years, a specimen tree begins to show off an artistic patchwork of green, yellow, brown, purple, and red bark over the fall and winter months.

Don’t wait. Lacebark pine is one of the first trees to plant in your landscape. With maturity (age) comes beauty. Give this medium sized pine lots of room, planting in full sun and it will reward you in 20-25 years. A mature tree reaches 30 – 50 feet tall and 20 – 25 feet wide and has a long lifespan. This pine is moderately drought tolerant and, once established, requires little care.

Shrubby when young, this tree has picturesque, showy bark that exfoliates or peels in patches, revealing a patchwork of colors of white, olive, light purple, and silver. Its mottled bark (see photo below) stands out from other pine species. The patchwork bark will eventually mature to a milky white. Bark features gradually becomes more evident as the tree ages. Excessive pruning or fertilizing isn’t necessary; the tree does benefit from a single annual application of slow-release fertilizer in late winter to stimulate growth.

This tree is monoecious, and the pollen cones are ornamentally insignificant. The male pollen cones standout with yellow pollen sacs, cylinder-shaped, and clustered. Female pollen cone is yellowish green.

A young lacebark pine is best trained to single-trunked or multi-trunked. Annual pruning is unnecessary. However, you may desire to lop off lateral branches to reveal its ornate bark along the trunk(s) and lower branches. Remove dead, pest-riddled, and/or dying branches in any season.

Old Lacebark pine at Bronx Botanical Gardens in NYC

In general, lacebark pine is long-lived and not seriously troubled by most disease and insect pests like caterpillars. Be watchful for aphids, borers needle rusts and diplodia tip blight.

Leading Cultivars: P. bungeana ‘Silver Ghost’ (30 feet silvery-white needles, mottled bark), P. bungeana ‘Temple Gem’ (30 feet pyramidal form), P. bungeana ‘Rowe Arboretum’ (20 feet tall compact, densely branched)

Three Native Azaleas That Should Be Included In Mid- Atlantic and Southern Gardens

Posted by Hugh on March 25th, 2024

About Native Azaleas: Flowers appear from April to September depending on species. Flower clusters (called “trusses”) appear just before the leaves emerge. Each truss may bear 3 – 12 blooms, which open 1.5 – 2 inches wide. Flower colors vary among native species from white, pink, orange and red shades. In many spring blooming species, the open petals curve back to show off the long stamens and styles that protrude from the flowers. Among the 15 azaleas native to the Eastern and Southern U.S., flower fragrance is wonderfully aromatic in some; others emit no fragrance.

Three of my early spring blooming favorites are highlighted here.

Coastal azalea (Rhododendron atlanticum) is a compact, loosely branched, stoloniferous, suckering, deciduous shrub that typically matures to 2-3 feet tall and as wide, but infrequently grows to 6 feet. In April 1.0-1.5-inches long white flowers are flushed with pink, bloom in multiple clusters of at the time of or slightly before the appearance of new leaves. Stamens protrude well beyond the corolla mouth. Flowers have a wonderful musky fragrance. This azalea is native to coastal plain areas from New Jersey and Pennsylvania south to Georgia. It spreads by underground stolons. (Zones 5-8).

Florida Flame Azalea (R. austrinum), not to be confused with Flame azaleas (R. calendulaceum) blooms within days after Coastal Azalea in shades ranging from sunny yellow to deep gold, tangerine, or apricot. Blooms strut showy protruding stamens and are highly fragrant. It is native to woodland slopes and mountain balds in the Appalachian Mountains from Pennsylvania to Georgia. (Zones 6-9). Shrubs are upright branched and typically grow 4 to 8 feet tall (infrequently to 10 to 15 feet) and 8 to 10 feet wide.

Pinxterbloom azalea (Rhododendron periclymenoides), formerly R. nudiflorum, is a hardy deciduous azalea native to a large geographic area of the eastern U.S. Pinxterbloom prefers a humus-rich, well-drained soil. Pinxterbloom grows to heights from 4-8 feet. The slightly fragrant flowers are generally pale pink but colors may range from white to deeper purple in natural populations. It spreads by underground stolons and shrub may become densely branched. (Zones 4-9).

General Care: A partly shaded or dappled sun site is preferred. Heavy woodland sites limit flower numbers. Deciduous azaleas prefer consistent moisture, and well-drained soil. Water after planting and every 5 days over dry periods lasting 10 or more days. Mulching with 3–4-inch layer of pine needles, wood bark, or compost helps conserves soil moisture and maintains cooler soil temperatures.

Deciduous azaleas are pruned within 4-6 weeks after seasonal flowering has finished. Prune to desired shrub size and remove broken or dead wood. Protect against strong winter winds and spring frosts to prevent leaf scorch and blossom injury. Disease and insect problems are infrequent when these 3 native azaleas are properly sited. Flowers will attract butterflies, bees, and hummingbirds.

Ten Favorite Viburnums

Posted by Hugh on March 18th, 2024

Viburnums are versatile landscape shrubs that flower, fruit, and fall color. Several species have fruit that attracts birds and may persist most of the winter. To have the best cross-pollination and fruit display plant in groups rather than as specimens. Viburnums tend to prefer slightly acid soil. They have few pest or disease problems and need little pruning if they are selected and properly sited.

Korean Spice (V. carlesii) small white flowers, opening from pink buds, are highly fragrant from several feet away. sweet, rich, and complex with a hint of cloves. It has an attractive wine-red fall foliage on a compact, spreading 4- to 5-foot-high shrub. (Zones 4-7).

Mohawk hybrid viburnum (V. x burkwoodii ‘Mohawk’) has showy fragrant flowers and will attract wildlife to your yard. (Zones 4-8). Mature plants have excellent heat and drought tolerance; foliage turns maroon in fall but remains evergreen in zones 7 and 8.

Cayuga viburnum (V. x carlecephalum ‘Cayuga’) has a 4-10 feet tall and wide compact growing habit along with 4-inch snowball-shaped fragrant blooms in spring. (Zones 4-8).

Doublefile viburnum (V. plicatum f. tomentosum), with stately horizontal branches on a 10-foot-tall shrub. ‘Shasta’ and ‘Mariesii’ are beloved for its layers of broad, flat, white flower clusters, though it bears little fruit. Its crinkled deep green leaves take on a burgundy tint in autumn. (Zones 5-8).

Judd viburnum (V. x juddii) grows only 6 – 8 feet tall and 6 -10 feet wide, with an upright rounded form. pink buds open to snowball clusters of fragrant white blooms in the spring, reds and purple fall color. In some years its dark green leathery foliage turns red in autumn. (Zones 4-8).

Chinese Snowball viburnum (V. macrocephalum) grows up to 25 feet tall and 20 feet wide with a rounded vase-shaped form. Flowers are the largest of the snowball viburnums with profuse dome-shaped, rounded, infertile flowers in spring and some secondary bloom in the fall. The flowers emerge chartreuse and quickly turn white, sterile, and no fragrance. (Zones 6-9).

American cranberrybush viburnum (V. trilobum). Shiny red fruits (not true cranberries) follow the white flowers if they are pollinated from another plant, and broad leaves, almost maple-shaped, has distinctive trilobed leaves that turn bright red in autumn. Redwing (‘J. N. Select’) grows up to 10 feet tall and 8 feet wide. (Zones 2-7).

Arrowwood viburnum (V. dentatum) grows in full sun to part shade and range from 5-10 feet in height depending on cultivar. The broad white flower clusters that come in June are fragrance-challenged, but they mature into blue-black berries that birds love. ‘Blue Muffin® and Autumn Jazz® (‘Ralph Senior’) have reliable fall color. Chicago Lustre™ (‘Synnestvedt’) produce shiny blue berries in autumn. (Zones 2-8).

Blackhaw viburnum (V. prunifolium) is a 15-20-foot-tall tough utility shrub or small tree. It produces creamy flower clusters in May and pink fruits that eventually ripen to black; fruits are edible for humans as well as birds. (Zones 5-9)

Possumhaw, Witherod viburnum (V. nudum) is represented by two outstanding 5-6 feet tall cultivars– Brandywine™ (self-fruitful) and ‘Winterthur’ bear 2-5-inch-wide flat-topped flower clusters in May-June attractive glossy dark green leaves thru summer, and a stunning display of rosy pink and dark blue fruits in fall. Both varieties follow up with plentiful clusters of tart berries that start out light pink to deep pink and ripen to blue to purplish-black fruits; plant two or more for best fruit numbers. (Zones 5-9).