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

Snowdrops (Galanthus)

Posted by Hugh on December 6th, 2023

Snowdrops (Galanthus nivalis) are one of the first flowers to bloom in the spring. Depending on the region where you live, snowdrops appear in the early days of spring; often snow still blankets the ground. Snowdrops are tiny plants (3 – 6 inches tall) that produce multiple small showy, white, bell-shaped flowers, which hangs off the ends of green, leafless stalks. When the bloom opens, three outer petals arch out over three inner petals. The grayish-green leaves emerge first into 3-4 inches long strap-like blades.

Snowdrops pop up in mostly deciduous woodlands (maples, lindens, ornamental cherries, dogwoods, oaks, etc.). Winter light should average 6 or more hours of filtered sunlight. Plant snowdrop bulbs in a loose, humus-rich, well-drained soil. Snowdrops do not thrive in heavy clay.

The most common varieties planted in U.S. and Canadian gardens: Common snowdrops (Galanthus nivalis) grow 6-8 inches tall with many varieties including G. nivalis ‘Flore Pleno’, a double white flowering form (zones 3-7). Giant snowdrops (G. elwesii) grow 10 -12 inches tall and include varieties ‘Polar Bear’ and ‘Mount Everest’ (zones 3-8). If you are a snowdrop hobbyist, mark garden patches with a variety (cultivar) label.

David Culp’s Snowdrop Patch at Brandywine Cottage in PA (summer dormancy period)

Plant snowdrop bulbs 3-inches deep in soil that you have thoroughly cultivated. Space bulbs 3-4- inches apart. The bulb tip should be set in hole facing up. In late fall add a thin 1–2-inch layer of compost to provide the nutritional needs for next year’s bloom. Spreading a bulb fertilizer may give snowdrops a slight growth boost after flowering. Snowdrops will often naturalize. Lift and divide crowded bulb clumps if you wish to increase the total numbers of snowdrops or trade with garden friends.

Glory-of-the-snow (Chionodoxa), Crocus (Crocus spp.), Winter aconite bulbs (Eranthis hyemalis), Virginia Bluebells (Mertensia), and Bloodroot (Sanguinaria) are excellent companion plants with snowdrops in a woodland or rock garden setting. Do not buy snowdrop bulbs too far ahead of planting time to avoid them from drying out.

Snowdrops are resistant to deer and rabbits and are poisonous to pets and humans. Wear gloves when handling bulbs or plants to avoid possible skin irritation.

Naturalized multi-year planting of snowdrops

Foster Holly

Posted by Hugh on November 30th, 2023

Foster holly (Ilex x attenuata) is an old holly favorite which has not lost its sizzle. Cultivars of Foster Hollies were selected by E.E. Foster of Foster Nursery in Bessemer, Alabama in the 1950s. It is utilized in a number of landscape options across the Southern Appalachian region (USDA zones 6 and 7), including in containers in zones 7 and 8.

Back in the 1940’s, five selections of Foster hollies were introduced by E. E. Foster of Foster Nursery in Bessemer, AL. Eighty years later, the berry producing variety, ‘Foster #2’, remains highly popular; it produces a bountiful yield of small bright red holly berries. Fruits continue to be effective throughout the winter and are an important food source for many birds. ‘Foster #4’ is its male pollinator mate, but in most locales, male American hollies (I. opaca) also pollinate Foster #2.

*Ilex x attenuata* ‘Sunny-Foster’ -gold-leaf form

Foster hollies grows fast into small 12-30 tall trees or shrubs. They exhibit a strong vertical presence when utilized as specimen or foundation shrubs in front of tall edifices and on the corners of homes and apartment buildings. Foster holly is an excellent choice as a privacy screen.

For the artistically minded, fashion these hollies into almost any topiary plant form. Leaf spines are soft, not sharp as on some holly species. Female plants produce large quantities of berries. Cut boughs are decorative around the Christmas holiday period. Foster hollies are not utilized as foundation plants as they quickly outgrow their planting area (see photo below).

Unfortunately, Foster hollies are not commonly found in nursery commerce for sales. Ask local nurseries and full-service garden centers to source them for you.

Foster hollies planted too close to building

Hollies (Ilex spp.) grow in a moderately acidic (pH 5.8 – 6.5), well-drained soil and in full to partial sunlight. Feed with a water-soluble acidic fertilizer such as Miracle-Gro™, Miracid™, or Hollytone®.

Amaryllis Make Great Holiday Gifts

Posted by Hugh on November 22nd, 2023

Amaryllis at Biltmore Estates in Asheville, NC

What do you gift the gardener friends in your life? Let me suggest a flowering amaryllis bulb or one that is blooming in the plant shoppe. Amaryllis is a tropical bulb that blooms indoors usually in winter season (USDA hardiness zones 9-11). It is a big, beautiful bouquet that is among the easiest plants to grow. A single amaryllis bulb is a flowering dynamo. Simply, you just plant the bulb into a container and add water.

There are many varieties and colors to choose. Usually, local garden centers sell bulbs starting in early fall and offer some already blooming. Bulb size is important. I recommend purchasing large size bulbs over 30 cm across that produce several bloom stalks and greater numbers of flowers. For example, a 34 cm bulb size should produce 2-4 bloom stalks, each bearing 3-4 flowers. The newly potted bulb should flower in 6-8 weeks if room temps are between 68-72°F. Newly purchased amaryllis bulbs should be planted immediately or can be stored over several months in a cool dark (40-50°F) dry place prior to potting.

Amaryllis blooming at Biltmore Conservatory

Select a pot with a wide base, large enough to accommodate the new bulb. Fill the bottom of the container with fresh potting media and set the bulb on top. Finish filling and packing the potting mix. Leave 1-2 inches of the bulb top (the shoulders and neck) exposed. Thoroughly water the potting media to settle the bulb. Place the pot in a cool (60-70°F) location and in bright light indoors or one-half day morning sunlight outdoors. The bulb is dormant and ready to sprout. A bulb potted in early November should be blooming by New Year’s Day.

Continue to water as needed after shoots and flower buds have emerged. Rotate the pot ¼ turn every 4-5 days to keep the stem growing straight up and not bending toward the window light. Avoid overwatering that may cause the amaryllis bulb to rot. The large flowers may become top heavy. If needed, stake the flower stalk for additional support.

Blooms last longer if you can keep them away from direct sunlight and dry heat. As the individual flowers fade, snip them off with a sharp knife. Eventually, cut back the entire bloom stalk to about an inch above the bulb.

Want to rebloom your amaryllis? Simply stop watering in the fall and store the potted bulb in a cool storage area and very low light for 2-3 months. Clip off the old dried leaves have dried up and the bulb is now dormant. Starting in late January or February, restart the amaryllis by watering it. It should rebloom in 6-10 weeks at room temperature.

Amaryllis bulbs will re-bloom annually in the same pot for several years. After spring freeze and frosts are over, move amaryllis outdoors into ½ day of sunlight (full morning preferred) and protect from drying winds. From spring to early fall, continue to water as needed and feed monthly with a water-soluble fertilizer like Miracle Gro™ or Peters™. Bring the pot back indoors when night temperatures fall below 40°F.

Amaryllis bulbs make great holiday gifts for garden friends and neighbors. Brent and Becky’s Bulbs, an online bulb emporium in Gloucester, VA, lists many colorful varieties in their on-line catalog.

Substitutes For Callery Pear

Posted by Hugh on November 15th, 2023

Bradford Pear (*Pyrus calleryana* ‘Bradford’)

The end to planting Callery pears (Pyrus calleryana), aka Bradford Pear, is almost within sight as more states are banning sales of the tree at garden centers and box store garden departments. Recently, Ohio, South Carolina and Pennsylvania have banned further plantings.

This March blooming flowering tree has been determined to be invasive. It produces fruits in the fall which competes with native flora in many states. The average gardener will likely know the callery pear by its varietal name “Bradford pear”.

Callery pears are reliable spring bloomers, the trees covered with white blossoms for 2-3 weeks in late winter and early days of spring. In most years trees strut an exceptional crimson red leaf color in late autumn. Trees have few disease or insect problems, are adaptable to a wide range of soil conditions, and cope on urban sites.

Wild callery pears aggressively compete and frequently displace the native plant species growing on the site. They have invaded natural woodlands and parks. It has become a problematic tree as well. Callery pears are not a long-lived tree, rarely lasting more than 25 years. The tree has a weak structure at the “V” of the branches.

Tree branching is notorious brittle resulting in limb breakage during ice and windstorms, often resulting in the tree’s removal. Limbs snap off in areas from old age. Further, blooming trees emit an unpleasant fragrance. Seedling trees produce sharp pointed thorns which snag clothing during pruning or puncture tires if you attempt to drive over fallen branches.

Bradford pear flowers are self-incompatible, that is, they do not fertilize other ‘Bradford’ pears flowers. However, they successfully pollinate other callery pear varieties, such as ‘Redspire’, ‘Aristocrat’, ‘Chanticleer’, ‘Whitehouse’, and ‘Cleveland Select’ among others. These varieties produce tiny, hard pear fruits, each ½-inch in diameter, green to brown in color, and contain viable seeds. Birds or other animals eat these fruits and disperse the seeds across the countryside.

Consider these spring flowering trees when replacing Callery pears: Redbuds (Cercus spp.), Crabapples (Malus spp.), Flowering Dogwood (Cornus florida), Serviceberry (Amelanchier spp.), Flowering Cherries (Prunus spp.), and Carolina Silverbells (Halesia diptera). In mid-South locations, early flowering deciduous Magnolias are also better alternatives to callery pears.

If you spot wild callery pears seedling trees growing on your property, cut them down and paint the stump with any herbicide containing the ingredient Glyphosate® to prevent the tree from resprouting.

Planting Under Trees

Posted by Hugh on November 7th, 2023

*Selaginella braunii* at Biltmore Estate in Asheville NC in winter

Here is an idea that I picked up at Chanticleer Gardens in Wayne, Pennsylvania and pollinators will also love you for it. When planting a deciduous tree, make good use of the ground area beneath the tree by planting shade tolerant ground covers. Evergreen trees don’t work here. You can also create a beautiful planting bed of assorted perennials at the edge of a woodlands.

Many gardeners will automatically plant hostas, coral bells (Heuchera spp.,) or assorted ferns. All are great choices. Here is a lengthy list of long-lived shade perennials: Lenten roses (Helleborus x), foamflower (Tiarella), Hakone grass (Hakonechloa macra), woodland phlox (Phlox divaricata), Bigroot geranium (Geranium macrorrhizum), lilyturf (Liriope spicata), deadnettle (Lamium), lungwort (Pulmonaria saccharata), wild ginger (Asarum canadense), moss fern (Selaginella braunii), astilbes (Astilbe spp.), coralbells (Heuchera villosa), (Brunnera macrophylla), Spotted deadnettle (Lamium maculatum), hardy begonias (Begonia grandis), pachysandra, Ajuga (Ajuga reptans), barrenwort (Epimedium spp.), Pennsylvanica sedge (Carex pensylvanica), and two favorite shade ferns – Christmas fern (Polystichum acrostichoides) and male fern (Dryopteris filix-mas). Don’t leave out planting late winter blooming bulbous flowers such as snowdrops (Galanthus nivalis) and winter aconite (Eranthis hyemalis) or fall blooming rain lilies (Zephyanthes).

Dry shade is the area (or shade) found under a canopy of a huge, deciduous or leaf-shedding trees. It is called ‘dry’ since the area often lacks moisture partly due to the maturity of the tree. Low growing hydrangeas also work under trees with supplemental irrigation. Recommend Mountain hydrangeas Tuff Stuff® series or Let’s Dance® bigleaf hydrangea series (Hydrangea macrophylla), Summersweet (Clethra alnifolia ‘Hummingbird’ and dwarf Japanese andromeda (Pieris japonica). They won’t thrive under dry soil conditions.

Use an augur, hand trowel, or hori (digging knife) to set most plants. Opt to plant 3 or more of each variety for visual impact of the colorful foliage or flowers during the season. Add plants with bold colors or variable foliage textures. This can add beauty to your dry shade and would surely catch some attention.

Adding ground cover plants under established trees is rarely successful, particularly if the trees are shallow-rooted. As stated earlier, you might try to drill in small flowering bulbs like crocus and snowdrops deep rooted established dogwood, redbud or crape myrtle. Do not add 2 or more inches of topsoil under established trees in order to sow ground plants and bulbs. This would deprive tree roots of needed oxygen.

Rattlesnake Master

Posted by Hugh on October 31st, 2023

Rattlesnake master (Eryngium yuccifolium) is mostly at home in a hot sunny prairie environment in the Southeast and Midwest (USDA hardiness 3-8). Its spiny nature gives it a desert spiny yucca-like appearance. Some Indian groups were known to brew the plant’s roots as an antidote to rattlesnake venom. Some native peoples also used the dried flower stalks as ceremonial rattles. No, the plant does not attract rattlesnakes.

Rattlesnake master is a perennial herb in the carrot (Apiaceae) family. The iris-like plant grows 2-5 feet tall and 2 feet wide. It is characterized by alternate, long, narrow blue-green leaves with a sharp tip. Widely scattered stiff spines are formed along the leaf margins. Leaves measure up to 3 feet.

Rattlesnake master is an easy plant to grow. It grows in almost any soil, including clay soils, dry soil, even shallow rocky soil. Good soil drainage is highly important to this prairie inhabitant. Its water use is medium; once established, it can also withstand long drought periods lasting 3-4 weeks. It is highly resistant to diseases and insects. Deer and rabbits tend to stay away.

From July to September, thistle-like greenish-white flower balls, ½ to ¾ inch wide, are arrayed in ball-like clusters atop a tall smooth stalk. Each flower head is comprised of numerous small flowers with 5 white petals that emit a honey-like fragrance. Surrounding each flower is a whorl of prickly leafy bracts. It spends its first year developing a deep root system. Flowering often begins blooming in the second season. The garden should be in full sun and in lean (unfertilized) well-drained soil.

Leaves are mostly basal, long and sword-like with parallel veins and tapering to a sharp point, up to 2½ feet long and only 1-inch wide with a few smaller leaves ascending the stem. Leaf surfaces are waxy, the edges either smooth or commonly with widely spaced, fine spiny teeth. Stem leaves are stiff and typically wraps itself around the stem. Stems are hairless, blue-green, waxy, and ridged.

Seed propagation is your best option. Saved seed should be cold stratified at 40°F for two months and then sowed in spring. Established plants can be divided in late spring or fall. Plants do not transplant well. Likewise, deadhead spent flowers to avoid seed dispersal and self-sowing.

Extra: At Southeast Research and Extension Center in Lancaster County, Pennsylvania, rattlesnake master ranked in the top third of plants with the greatest total number of pollinator visits for both pollen and nectar. It is highly valuable bees, wasps, flies, butterflies, skippers, moths, beetles and other plant insects.

Other Eryngium spp. of garden interest: Oliver Sea Holly (E. x oliverianum) and Flat Sea Holly (E. planum ‘Blue Cap’).

January Blooming Vernal Witchhazel

Posted by Hugh on October 21st, 2023

This winter – follow your nose to Vernal witchhazel (Hamamelis vernalis), aka Ozark witchhazel. (USDA zones 4-8). This U.S. native witchhazel grows as a deciduous shrub to small tree. It may produce the smallest flowers of all witchhazel species, but they’re highly fragrant when little else is blooming. It naturally inhabits a wide area encompassing from southern Missouri to northwestern Arkansas and eastern Oklahoma.

New leaves emerge bronze to reddish purple and fall foliage finishes golden brown and often persists into early winter. Leaves are almost circular, measuring 2.5 to 5 inches long and wide, with a slightly oblique base and leaf tips are acute or rounded. Leaves are dark green above and glaucous beneath with a wavy-toothed or shallowly lobed margin and short, stout petiole.

Its dark yellow (gold) blooms appear from January to March and age to dusky red. Flowers are comprised of four narrow ribbon-like petals, barely ¼ to 1/3 inches long with four short stamens. On warm 50°F winter days, watch for bees buzzing around the fragrant blooms.

Tiny individual fruits (³⁄₈–⁵⁄₈ inch long) are hard woody capsules that split open to explosively at the apex at maturity one year after pollination, each one ejecting two shiny black seeds 30 or more feet from the parent plant. Three vernal witchhazel cultivars are:

‘Amethyst’ – has a rounded form, 8 to 10 feet tall and wide, and gray-green spring/summer foliage that turns a brilliant red and orange in autumn. Deep red purple flowers are lightly fragrant and finish reddish purple in mid-winter.

‘Quasimodo’ – a semi-dwarf selection (4 to 6 feet tall) introduced from a European nursery industry in 1980. Light orange flowers are highly fragrant, and compact-spreading habit. Spring foliage is rich greenish-blue and stays quite attractive throughout the growing season.

‘Sandra’- grows 6-10 feet tall and 8-10 feet wide with fragrant golden strap-like flowers from mid-winter to the first days of spring.

Vernal witchhazel spreads underground slowly via stoloniferous root shoots. Annual maintenance other than pruning is unnecessary. Maintain the natural shape of the shrub and rein in its root suckering to fit its intended landscape space. Annual fertilizing is generally unnecessary. If the summer foliage became chlorotic (yellow), apply 1-2 handfuls of elemental sulfur in the fall or feed with an acidic fertilizer like Miracle-Gro or Schultz in spring and early summer. Apply 3-4 inches of bark mulch or pine needles in spring.

Where to purchase: online native plant nurseries.

Burls on Tree Trunks

Posted by Hugh on October 12th, 2023

An unusual swelling on trunks of trees and occasionally on large branches are “burls”. They’re round, swollen-looking growths on tree trunks and large scaffold branches. Should or shouldn’t you be concerned? Burls are not uncommon and can be found on cherry, maple, oak, buckeye, ash, willow, locust and walnut in Eastern forests. Root burls may also be found on rhododendron and laurel.

The cause of tree burls is a bit of a mystery. Plant scientists don’t know why they occur. In general, burls develop because of invasions (bacteria, fungi, and insects) or stressors (freeze damage, mechanical, and environmental injury). Certain tree species are genetically predisposed to develop one or more burls while other nearby trees may not likely form any.

Are burls bad for trees?… Usually not. Burls typically don’t do any harm to trees. On rare occasions, a burl may disrupt the tree’s vascular (circulatory) system. As it turns out, though, getting rid of them may pose the significant risk. Cutting burls would leave large wounds on the tree’s trunk and branches, which could lead to an infection or weaken the tree’s structural stability.

Burls may occur on tree roots and go largely undetected. Also, it is best not to remove the bumps on tree branches or tree trunks. However, you may clip away sprouts that emerge out of the burls.

Burls themselves generally don’t cause problems for your tree, but you should try to determine the root of the growth and address it. Consult a certified tree arborist to determine the cause and solution.

Since burls can be a result of insect or fungi damage, inspect for signs that point to an insect or disease infestation. Look for small holes in the trunk and branches, sawdust, or insects crawling around. Also, inspect the trunk or branch wood for evidence of decay including cavities, missing bark, root damage or wounds.

Conifer species in Alaska (Photo courtesy of Mary C. Rice)

Finally, burl wood is expensive and treasured by woodworkers and carpenters alike. Consult a Certified Tree Arborist in your state or city by searching the International Society (ISA) directory.

Uniquely Different Weeping Mulberry

Posted by Hugh on October 3rd, 2023

Common (White) mulberry (Morus alba) is a fast-growing, medium sized, deciduous tree that typically grows to 30-50 feet tall and wide. It usually develops a wide-spreading rounded crown with age. This native to China is utilized either as a landscape shade and/or a fruit tree. (USDA hardiness zones 5-9).

White Mulberry prefers a rich, moist, well-drained soil and full sun. The tree tolerates a wide range of environmental conditions including moderate shade, pollution, salt spray, extreme heat, infertile soils, a wide range of soil pH, and moderate drought. It is notoriously shallow rooted.

Mulberries are easy to identify by their large lobed leaves and their edible fruits – a delicious treat as well as a weedy seed problem. Individual leaves may be unlobed, mitten-shaped, or 3-lobed. Mulberry trees are polygamo-dioecious; they produce only male or female flowers on one plant or both flower types are present on the same tree. In June and July, female trees produce an annual crop of white, red, purple or black fruits that resemble long, thin blackberries. Prune mulberry in late fall or winter to avoid sap bleeding in spring.

Mulberries are a popular food source for many species of birds. Unfortunately, the fruit and resulting bird droppings are messy and will stain pavements, automobiles and areas around the home. Weeping cultivars are mostly fruitless which limits its threat as an invasive species.

No serious insect or disease problems trouble mulberries. The tree is not deer resistant. Borers are troublesome in some years in the South. Whiteflies, scale, mites and mealybugs are occasional pests. Bacterial blights and leaf scorch, powdery mildew, and root rot are usually indicators of poor site selection.

Weeping mulberry trees are exceptional unique, trouble-free, and should be planted more. Three major weeping forms are available.

M. alba ‘Pendula’ has a dwarf weeping form that matures to 8-15 feet, sometimes to 20 feet height. It creates a unique and beautiful presence in any garden! Its matchless contorted trunk and branches are revealed from late autumn thru winter.

M. alba ‘Chaparral’ is a superior weeping, male seedless form that grows 8-12 feet tall and is equal width. This male fruitless selection produces yellowish-green catkins in spring.

M. alba ‘Nuclear Blast’ (‘Itoguwa’) is a 3-4 feet tall and wide shrub oddity! Thread-like foliage appears shredded or deformed.

Gooseneck Loosestrife

Posted by Hugh on September 22nd, 2023

Gooseneck loosestrife (Lysimachia clethroides) can be both a delight and a weedy nuisance – depending on where you garden. (USDA hardiness zones 3 – 8). This native of southeast Asia grows aggressively in some locations in the U.S. where it has escaped into woodlands, wet areas, and on sunny, sheltered mountainous slopes. The perennial has upright rigid branching which bear unique white flowers (racemes) that bloom from June through August.

Gooseneck loosestrife is a fast-spreading plant that prefers partial sun and moist well-drained soil. Keep this aggressive perennial in check as it spreads aggressively via rhizomes and may become weedy from seed dispersal. It grows less aggressive in shady, dry soils although flower numbers are fewer and growth may be leggy.

Gooseneck loosestrife grows 2 -3 feet height and 3 feet spread. It can also be utilized as a groundcover. Leaves are slender with a tapered point. Raceme flowers average 12-18 inches in length and pure white. The fall foliage takes on gold to yellow tints. In northerly latitudes, gooseneck survives frigid winters by blanketing a 2–3-inch layer of mulch around the plant base.

In early spring, cut back all the stems to within 2 inches of the ground. Spring growth emerges from the crown and flowers appear in June until October. Keep it cornered in planting areas bounded by hardscaping. Every 3-4 years divide rhizomes in the spring to both limit its spread yet invigorate this rhizomatous plant. Judicious deadheading of spent flowers triggers reblooming and reduces seed formation. Flowers are particularly attractive to butterflies. It is relatively deer resistant.

Commercially, gooseneck loosestrife is produced by the cutflower florist industry. Floral stems may last over a week. Gooseneck earns its name for its flower spikes that mimic the curve of a goose’s neck.

Varieties:

‘Lady Jane’ (seed and vegetative produced) produces pure white blooms in late summer.

‘Geisha’ grows 2 feet tall with creamy yellow margin foliage; less aggressive (tamer) than species; 1-foot-long nodding white flower racemes in late summer.