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

Summer Blooming Amur Maackia

Posted by Hugh on July 7th, 2021

Amur maackia (Maackia) is a small deciduous tree with a broad, rounded canopy. Typically, it grows in cultivation at a slow-to-moderate rate to a height of 20-30 feet (to 60 feet in wild). This compact growing tree is an ideal fit in smaller landscapes. A botanical member of the Pea family (Fabaceae), it grows in the region of the Amur River in Manchuria and Korea and eastern Russia and China (USDA hardiness zones 3 to 7).

Compound, odd-pinnate, dark olive green leaves (7-13 leaflets each) are attractive in summer. The deciduous compound leaves emerge silvery-green in spring changing to medium green in summer. Each compound leaf measures 8 to 12 inches long and open grayish-green and matures to dark green. Expect a very slight reddish leaf color change in autumn.

Maackia prefers in full sun to part shade and moist, well-drained soil that is either acidic or alkaline. Its roots enrich the soil by adding nitrogen. It grows in a wide range of soil conditions. Florida horticulturists report that maackia is highly drought tolerant. Maackia has no serious insect or disease problems.

Few landscape trees bloom in early summer. Its fragrant oft-white pea-like flowers start to open in mid-June (In Tennessee). Blooms are clustered in showy 4 to 6 inch bundles and lightly fragrant flowers are pollinated by bees. Flowers are followed by flat 2-3 inches long seed pods, legume pods look like redbuds (Cercis).

Mottled olive-green bark adds to winter interest. Bark is copper-brown and starts peeling with age, a winter asset.

Available Cultivars:

MaacNificent® (M. amurensis ‘JFS-Schichtel1’) – very cold hardy cultivar (zone 3) with a vase-shaped habit and yellow fall color; grows 30 feet high x 20 feet wide.

Summertime™ – a more cold hardy cultivar (zone 3) selected by University of Minnesota. A round form; grows 15 to 20 feet high x 12 to 15 feet wide.

subsp ‘Buergeri’ – 20 to 30 feet tall (zone 4 hardy)

Amur maackia

Black Snakeroot (Bugbanes) For Woodland Beauty

Posted by Hugh on July 1st, 2021

*Actaea racemosa* at Kingwood Center, Mansfield, OH

The bugbanes (Actae spp.) represent a varied botanical genus. In my opinion, the most attractive and easy to grow perennial form is black cohosh or snakeroot (Actaea racemosa), formerly (Cimicifuga racemosa). It is a tall growing U.S woodland native (USDA hardiness zones 4 – 8).

Bugbanes are beloved for their tall architectural floral spikes. Small, numerous, creamy white, fragrant flowers form on wiry stems. Tall floral spires (typically 1-2 feet long) arise above the foliage in June – July or in September depending on locality. Full height (foliage plus flowering spikes) is 4 to 6 feet, sometimes to 8 feet when the growing environment if ideal. Its lacy astilbe-like foliage may be either a deep green or dark purple, related to the cultivar chosen.

Bugbanes prefer rich moisture-retentive soils and partial to full shade. Abundant soil moisture is of key importance. Allow plants 1-2 years to establish after planting as bugbanes tend to be slow. Ideally, plants thrive in 2-3 hours of morning sun, although they prosper in shady areas where light is reduced. Flower spikes are less if soil is excessively dry and under dark shade. Plant in an area protected from strong and/or drying winds.

This plant offers a vertical floral look planted in the rear garden border or in a woodland setting. The leaves are attractive and the showy flowers are followed by cool seedheads, often utilized in floral arrangements. Flowers exude an unpleasant medicinal smell. It is attractive to wildlife.

Disease and insect troubles are rare. Rust and leaf spot are occasional problems. The taller flower spires sometimes may require staking support. Flower spires tend to twirl directionally toward the morning – afternoon light source. Leaf edges may scorch in dry soil or under low humidity.

Cultivar: ‘Atropurpurea’ – purple foliage, dark tint in high light areas.

Actae pachypoda and Actae simplex are related species. Both are equally garden worthy.

Seven Picks For Your Summer Shade Garden

Posted by Hugh on June 26th, 2021

1. Coleus (Solenostemon) are known for their colorful foliage in containers around trees or shrubs. For shady areas select the Kong Mosaic™ or Wizard™ series.

2. Begonias, as a group, represent lots of variety series. Most garden begonia varieties should do well in beds, planters and pots. Begonia types like the Rex and Angel Wing are grown primarily for colorful foliage and, secondarily, for flowers.

3. Impatiens are not just for shady garden spots anymore. Choose hybrid disease resistant cultivars of Sunpatiens, New Guinea, and Beacon™ series. Impatiens offer showy, season-long blooms and perform best in partly sunny to partially shaded areas.

4. Caladium are non-hardy tubers; they are often started indoors in late winter to extend their outdoor seasonal performance. They are grown for their colorful tropical foliage which brightens up shady areas.

5. Fuchsias are readily identifiable by their drooping, brightly colored flowers that bloom most in spring, late summer, and early fall. Summer heat slows down blooming. Select the trailing forms which offer better performance in flower beds or hanging baskets.

6. Wishbone flower (Torenia fournieri) bloom from late spring into early autumn. Summer Wave® series is the current favorite with heat tolerance and hold up to occasionally dry soils. Plants grow 6 – 10 inches tall and trail 24 – 30 inches wide.

7. Boston fern (Nephrolepis exaltata) are excellent shade plants, traditionally planted in hanging baskets and window boxes. Asparagus fern (Asparagus springeri) is also nice addition to a shady spot.

All seven shade annuals look great in the front of landscape beds or in large patio containers and hanging baskets. Plants are set out in spring when threats of frost have left your area. All prefer moist fertile soil garden soil and partial shade. They perform in summer heat and humidity and underperform in deep shade.

Avoid Mulch Volcanos

Posted by Hugh on June 22nd, 2021

Ever heard of a “mulch volcano? It is a load of mulch that is piled up around the base of a landscape shrub or tree. A common answer I get from homeowners guilty of this practice is that they see professional landscapers and city maintenance crews doing it.

Volcano mulch can also cause tree roots to encircle the tree trunk. Eventually, this develops stem-girdling roots associated with volcano mulch, particularly on shallow rooted species like elms and maples.

Mulch volcanoes do not occur in nature and are all man-made. In fact, the practice may cost 2-3 times because of the excess mulch materials and installation cost. Result: 1. trees don’t grow, 2. their life expectancy is greatly reduced, and/or 3. the tree dies. Thick mulch layers develops tree health problems —suffocation of roots, loss of the root systems, and trunk girdling.

The injurious effect of mulch volcanoes occurs over multiple years. Initially, tree growth appears abnormal. Tree structure is weakened and become a liability to pedestrians, autos, and property owners. Insects such as scale insects and borer make their homes in the decaying wood. Disease pathogens also have an easier time invading the trees via the wounds.

Piling mulch around tree trunks has been a bad practice for decades. As the mulch decomposes and dries out, it becomes hydrophobic, that is, the organic mulch dries out; or becomes hydrophobic. You can observe hydrophobicity of dry organic matter when you try to moisten a bag of dry peat moss.

Remedy: First, inspect the trunk itself by removing the decaying mulch. Expose the decayed area to the air and treat decaying areas with insecticides. If you are unsure how to proceed, contact a certified tree arborist in your area.

Attracting Hummingbirds

Posted by Hugh on June 16th, 2021

In early spring many area gardeners rush to set out hummingbird feeders filled with a sugary solution to encourage these feathery critters to visit. However, the sugary drink also attracts ants, bees, and wasps. The solution does not furnish vitamins, minerals, and carotenoids that hummingbirds pick up from pollinating flowers and eating insects. In addition, in
garden beds and containers, offer hummers garden spaces to nourish on their favorite pollinator plants.

Red cardinal flower (*Lobelia cardinali*s)

Favorite Hummingbird Plants:

Perennials:
Anise hyssop (Agastache spp.)
Foxglove (Digitalis purpurea)
Daylilies (Hemerocallis spp.)
Blazing Star (Liatris spicata)
Red cardinal flower (Lobelia cardinalis)
Great blue lobelia (L. siphilitica)
Lupine (Lupinus perennis)
Beebalm (Monarda spp.)
Catmint (Nepeta spp.)
Beardstongue (Penstemon spp.)
Garden phlox (Phlox paniculata)
Sage (Salvia spp.)

Woody plants:
Mimosa tree (Albizia julibrissin)
Trumpetvine (Campsis radicans)
Summersweet shrub (Clethra alnifolia)
Rose of Sharon (Hibiscus syriacus)
Coral honeysuckle (Lonicera sempervirens)
Rose of Sharon (Hibiscus syriacus)
Coral honeysuckle (Lonicera sempervirens)
Azaleas and rhododendrons (Rhododendron spp.)
Weigela (Weigela florida)

Annuals:
Cuphea, cigar plant (Cuphea)
Impatiens
Lantana
Flowering tobacco (Nicotiana)
Salvia (Salvia spp.)
Snapdragons (Antirrhinum)
Zinnia (Zinnia elegans)
Cypress vine (Ipomoea quamoclit)

Caveat: change the hummingbird feeding solution every 4-7 days during warm spring and summer weather. The sugary feeding solution gradually ferments and clouds up with bacteria which may be fatal to birds.

Shorter Version Of Six Landscape Shrubs

Posted by Hugh on June 11th, 2021

Sugar Shack™ Buttonbush (Cephalanthus occidentalis Sugar Shack™) – Full Sun (6+ hours), Part Sun (4-6 hours), Full Shade (up to 4 hours). 3 to 4 feet tall and wide. cut the size in half and added colorful red fruit and glossy foliage. Add in cool looking, fragrant white flowers and you’ve got a delightful plant that shines from spring to fall (zones 4-10).

Hummingbird Summersweet shrub (Clethra alnifolia ‘Hummingbird’) – native summer blooming shrub with showy, wonderfully fragrant flowers that attract bees, butterflies and hummingbirds; attractive, glossy dark green leaves set off pure white summer flowers. Plant it near the deck or patio to enjoy the sweet scent in mid-summer; extra large blooms with equally large individual florets; deer-resistant (zones 4-9).

‘Little Henry’ Virginia Sweetspire (Itea virginica ‘Little Henry’) – a lovely compact, late spring native shrub. Beautiful display of fragrant white flowers over 2-3 weeks; glossy green disease-free spring/summer foliage; stunning garnet-red in fall; deer resistant (Zones 5-9).

Pugster Butterfly bush (Buddleia x) – compact plant just 2 feet tall and 2-3 feet wide, large full flowers in three color choices: Pugster Blue®, Pugster Amethyst®, and Pugster Pink®. Full sized long-blooming true-blue or pink fragrant flowers from mid-summer into fall; no deadheading needed; drought tolerant; blooms attracts bees, butterflies and hummingbirds; deer and rabbit resistant (Zones 5-9).

Low Scape Mound® aronia (Aronia melanocarpa) – tough, low-growing native groundcover shrub, providing beauty from spring through frost (zones 3-9). It forms a low 12-24 inches high by 18-24 inches wide shrub and ground cover. Leaves are glossy green. In spring, it’s covered in hundreds of dainty white flowers, and in autumn, the leaves turn brilliant red to contrast with dark purple-black fruit. It thrives almost anywhere: cold climates and hot ones, wet soils and dry ones, sun and part shade.

Double Play® Candy Corn™ Spirea (Spiraea japonica Double Play® Candy Corn™) – an eye-catching 18-24 inch tall compact shrub; new leaves start out brilliant red, later orange, eventually summer foliage turns sunny yellow with new leaves emerging orange; rich purple flowers in late spring make this spirea the most flamboyant member of the Double Play® Series. (Zones 4-7).

Three Cool Sedges (Carex)

Posted by Hugh on June 6th, 2021

*Carex* ‘Everillo’ at NC Arboretum, Asheville, NC

Over the past decade Japanese Sedges (Carex spp.) have become popular in U.S. gardens. Uncertain which ones to plant – here are three that are easy to grow and require little maintenance. The following three clump-forming evergreen Japanese sedges flaunt arching, green and white variegated grass-like foliage. Tiny insignificant, brown flower spikes arise on long stems in summer. All three are hardy in zones 5-9.

‘Everillo’ (Carex oshimensis) is one of seven varieties in the Evercolor® Carex series. Plants form a cascading mound of bright, lime-green leaves that turn yellow-gold as they mature. More sun intensifies the yellow, while the foliage turns chartreuse with increasing shade. Plants average 12-15 inches high x 24 inches wide and elegantly bright golden weeping foliage.

1 Year old planting of *Carex morrowii* ‘Ice Dance’

‘Ice Dance’ (Carex morrowii) enlivens the landscape with vivid deep-green centers and creamy-white margins on half-inch-wide leaves. Ice Dance spreads via slow to medium growing rhizomes into a grassy groundcover. Plants average 10 – 16 inches in height and 18 – 24 inches in spread. As an added bonus, Ice Dance maintains its cool color in winter in mild growing zones and and is semi-evergreen in colder climes.

‘Feather Falls’ (C. oshimensis) is recognized for its fountain-like green and white variegated leaves that hold its rich green color over the coldest of winters. Feather Falls sedge is new in the marketplace and may be hard to purchase at this time. The plant is a standout either grown by itself or in mixed container on a patio or deck. Feather Falls grows 16 inches high and 24 inches wide.

These clump forming perennial sedges thrive in sun and or moderate shade. Plants don’t grow much when it is hot. Plants stay evergreen where winters are mild. As previously stated, no clipping is needed. However, a rough winter may injury the foliage; if so, clip back the plant accordingly.

Divide cool season grasses in spring or early fall. Plant sedges in spring, thru summer, but no later than early October so plants don’t heave out of the ground. Feed sedges with a slow-release fertilizer (Osmocote™ or Nutricote™) at planting time and in early spring. Irrigate during dry summer periods. Sedges are deer resistant planted in garden beds, borders, woodland gardens, and containers.

Growing Cosmos

Posted by Hugh on May 26th, 2021

Cosmos are native to Mexico. In the U.S. these old-fashion annuals bloom throughout the summer months and attract birds, bees, and butterflies to your garden. They produce colorful 2- to 4-inch wide daisy-like flowers that sit atop 3-5 feet tall slender stems. Cosmos make excellent cut flowers and dwarf forms are ideal in containers.

Annual cosmos grows in average well-drained soils and in partial to full sun. To avoid staking cosmos, tall varieties are best in full sun and in poor, fairly dry soils. Over-watering and over-fertilization can lead to plants with fewer flowers. Shelter cosmos from strong winds. Plant taller plants close enough for plants to support one another. Deadhead spent flowers to prolong bloom, but just enough flower heads for self-seeding.

Cosmos are low-maintenance annuals. Summer medium green leaves are deeply cut into threadlike segments. Floral colors range from red, pink, orange, yellow, white, and bi-colors. Cultivars feature single, semi-double or double flowers that range in height from dwarf (1.5 feet) to tall (6 feet). Floral heads may be flat or cup–shaped.

Two species are commonly listed in plant and seed catalogs. Cosmos bipinnatus come in pink, red, white, lavender, and bicolors. C. sulfureus come in yellow, orange and scarlet orange, and bicolors. Some varieties produce semi-double flowers. Deadheading dead or faded flowers encourages more flowering and better branching by pinching out the central shoots or stem tips. Some varieties grow very tall and may require staking. Mostly trouble-free, powdery mildew, stem cankers, aphids can be occasional problems.

Gardeners may opt to direct seed cosmos. For earlier flowering start the seeds indoors 6-8 weeks before the late frost forecast in your region. Cosmos self-seed readily. Either purchase seeds at garden shops or collect dried seeds late in the fall to sow next year. Know that seeds from hybrid varieties may not “come true” to the parent plant.

Varieties: C. bipinnata ‘Radiance’ (wine red), ‘Candy Stripe’, ‘Daydream’, ‘Sensation’, ‘Sunny Red’.

C. sulphureus ‘Bright Lights’, ‘Cosmic Orange’, ‘Lemon Twist’, ‘Klondike’ (orange).

Little Leaf Linden

Posted by Hugh on May 21st, 2021

Littleleaf linden

Littleleaf linden (Tilia cordata) is highly praised as an excellent urban shade tree. The species reaches 60 to 70 feet tall and spread of 30 to 40 feet. The foliage tolerates several urban pollutants. This durable tree is often utilized as a street and park tree because of its environmental adaptability. Two year old established are moderately drought-tolerant. It is easily grown in an average, well-drained, moderately acidic soil and in full sun (USDA hardiness zones 3 to 7).

Three-inch-long, shiny, dark green, ovate to cordate leaves persist through autumn. Fall leaf color turns pale yellow-green and is rarely remarkable. Tree blooms abundantly in June and the unusual, early summer flowers are both showy and fragrant. Small clusters of creamy yellow flowers form dangling cymes.

Flowers morph to become single winged nutlets through summer as they ripen in late summer. Flowers attract butterflies and bees and linden honey is highly rated.

Littleleaf linden seems not to be troubled by significant insect or disease issues. Injury from Japanese beetle feeding is often temporary and new aftergrowth masks leaf feeding. Pesticide applications over the first three years is recommended.

There are a number of cultivars available on the market, each with slightly different ornamental or size characteristics. Indigenous to Europe, all kinds of lindens are popular as tall hedges and windbreaks.

‘Chancellor’ grows more compact than the species, to about 50 feet high; the upright, habit of young trees becomes more pyramidal with maturity.

‘Greenspire’ is a shorter version of the species, grows 50 feet tall and develops a neat pyramid shape.

Shamrock® (T. cordata ‘Baileyi’) is similar to Greenspire, with a more open crown, spreading 30 feet wide.

Summer Sprite® (T. cordata ‘Halka’) is a compact selection with a rounded shape, reaching only about 20 feet high and 15 feet spread.

‘June Bride’ grows 30 to 45 feet tall and 25 to 30 feet wide; displays a slower growth rate with a dense pyramidal to oval crown.

Ashe Magnolia

Posted by Hugh on May 16th, 2021

Ashe magnolia (Magnolia macrophylla subsp. Ashei) is a small 10-20 feet tree with enormous leaf and flower sizes (zone (5)6-9). Anindividual white flower measures 6- 12 inches across with a purple blotch at the base of 3 inner petal-like tepals. Ashe magnolia blooms in late May – early June in Tennessee. Many of the white blooms may be hidden within the large tropical-like foliage.

Within the large leaf magnolia species, Ashe magnolia is the shortest — the runt of the litter. Its deciduous leaves are 10-16 inches long and 12+ inches wide. Leaves are wider near the tip than at the stem, green on the upper surface and whitish beneath. When fully open, the citrus-scented white blossoms reveal a purple blotch in center that is up to 6 inches long and about half as wide. Ashe magnolia blooms at an early age, usually when only 4-6 feet tall. A seedling may bloom as early as 3 years from seed.

Ashe magnolia is an understory tree, growing in day-long dappled sunlight or morning only sun. Allow Ashe magnolia plenty of room to grow, adequate light, and humus-rich, moist, well-drained soil. Don’t crowd other plants up around the tree. Lightly mulch around the tree to a depth of 3 inches. Over the active growing season, water the tree weekly over the 1-2 years until established.

Ashe Magnolia rarely needs to be fertilized unless growing potted. In a container, apply a slow release fertilizer such as Osmocote® or Nutrikote®. Life in a standard 5- gallon container is only 2-3 years and then it needs to planted in the ground or bumped into container 15 gallons or larger. For container-growing, dig a hole as deep as the container with a diameter to three times the width of the container. Fill the hole, water, and feed with a water soluble fertilizer like Miracle-Grow™ or Peters™.

Young Ashe Magnolia on East Tennessee State Univ. Campus in Johnson City, TN

Ashe magnolia does not thrive in hot and dry environs. The grand champion tree is 44 feet high in Montgomery County in Pennsylvania. In Florida, a tree grows in limestone-rich sandy or clay soil compared to a humus rich North Carolina clay soil. Sheltered sites are best since strong winds can shred the papery leaves and break the brittle branches.

Flower buds may be hurt by late-spring frosts in northern climes such as in New England. Prune in late winter or late summer to prevent bleeding of sap. Constructive pruning may be needed after storm damage and to maintain its desired tree framework.

Ashe magnolia is a tree that a plant collector will love. It is primarily available from a specialty e-mail nurseries. Request the tree’s seed provenance before purchasing. Select from a northern seed source if you garden in zones 6 or 7. The Florida Department of Agriculture lists the Ashe magnolia as endangered, due to its small population and restricted range.