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

More Cool Small Flowering Shrubs

Posted by Hugh on January 23rd, 2022

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

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

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

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

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

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

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

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

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

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

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

Four Tree Conifers Which Should Be Planted More

Posted by Hugh on January 16th, 2022

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

Glossy waxy clean needles of Nordman Fir

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

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

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

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

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

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

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

Golden larch on North Carolina Arboretum, Asheville, NC

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

So Many Great Amsonias

Posted by Hugh on January 11th, 2022

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

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

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

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

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

Fall color of Arkansas amsonia (*Amsonia hubrichtii*)

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

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

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

Three Popular Amsonia Species

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

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

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

2022 Perennial Plant Of the Year – Little Bluestem

Posted by Hugh on January 6th, 2022

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

Seasonal Transition in Color (Hoffman Nursery, Inc.)

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

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

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

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

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

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

Information sources: Perennial Plant Association and American Horticulture SocietyW

‘Standing Ovation’ little bluestem

2022 Perennial Plant Of the Year – Little Bluestem

Posted by Hugh on January 3rd, 2022

2022 Perennial Plant Of the Year – Little Bluestem

Summer/Fall Photo credit: Proven Winners

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

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

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

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

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

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

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

Information sources: Perennial Plant Association and American Horticulture Society

After The Holidays Poinsettia Care

Posted by Hugh on December 26th, 2021

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

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

True flowers in center surrounded by colorful bracts

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

Poinsettia Care

Posted by Hugh on December 21st, 2021

Poinsettias (Euphorbia pulcherrima) have become a symbol of Christmas and the winter holidays. Their colorful bracts (most people call them “flowers”) are actually modified leaves. Red remains the most popular color, but select from white, pink, burgundy, marbled, speckled and new “tropical shades”.

Buy a healthy poinsettia! The small yellow flowers in the center of the bracts (called “cyathia”) are fresh and not dried out or turning brown. If the cyathia have dried out, do not purchase. Once the flowers start to age, the colorful bracts soon decline. In the room do not set the plant close by a heat source or cold window. Pick up the pot — if it feels light, then water it.

Inside the typical home or apartment, poinsettia only needs water every 5-7 days. Before watering your poinsettia, remove the decorative pot covers or foil that most poinsettia varieties are packaged in. The pot cover can hold too much water, something a poinsettia does not like. Punch holes in the bottom of the covers and set on a saucer. Do not leave your plant pot(s) sitting in water over 3 hours as it may injure the roots.

Place your poinsettia near a sunny south- or east- facing window of your house or apartment. Room temperatures should be between 65 – 75 °F. Poinsettias thrive in a well-drained soil-less media (potting mix).

Feed the plant every 2-3 weeks with a water-soluble garden or house plant fertilizer @ one-half the rate on the package directions. Your poinsettia should continue to look pretty into the early days of spring.

Poinsettia Tree at Atlanta Botanical Garden

Poinsettia plants are NOT poisonous – The white sap is not toxic to humans, dogs and cats. Some people and pets may be sensitive to the plant’s sap which may cause a skin irritation. Some veterinary medicine websites state that poinsettias can be mildly toxic to dogs and cats and can cause vomiting, drooling, and, rarely, diarrhea.

Bird Friendly Trees And Shrubs

Posted by Hugh on December 16th, 2021

Birds visit trees, shrubs, and vines for five things: fruits (berries), sweet nectar (flowers), insects (particularly caterpillars), nuts and seeds, and shelter. This list is a compilation from the North Carolina and Tennessee chapters of the Audubon Society of ornamental plants common in the Southern Appalachian region.

Trees and Shrubs (26)

Maples (Acer spp.)

Downy Serviceberry (Amelanchier arborea)

River Birch (Betula nigra)

Beautyberry (Callicarpa americana)

Hickories (Carya spp.)

Dogwood (Cornus florida)

New Jersey Tea (Ceanothus americanus)

Hawthorns (Crataegus spp.)

Winterberry (Ilex verticillata)

Virginia Sweetspire (Itea virginica)

Eastern Red Cedar (Juniperus virginiana)

Spicebush (Lindera benzoin)

Sweetbay Magnolia (Magnolia virginiana)

Crabapples (Malus spp.)

Blackgum (Nyssa sylvatica)

Pines (Pinus spp.)

Wild Plum (Prunus americana)

Cherries (Prunus spp.)

Sweet Azalea (Rhododendron arborescens) – at higher elevations

Pinxterﬂower (Rhododendron periclymenoides)

Oaks (Quercus spp.)

Willows (Salix spp.)

Elderberry (Sambucus canadensis)

Sassafras (Sassafras albidum)

Arrowwood Viburnum (Viburnum dentatum)

Smooth Witherod (Viburnum nudum)

Woody Vines (3)

Trumpet-creeper (Campsis radicans)

Cross-vine (Bignonia capreolata)

Coral honeysuckle (Lonicera sempervirens)

Raked Leaves Improve Garden Soil

Posted by Hugh on December 9th, 2021

Don’t rake and send fallen leaves to urban landfills. In a recent poll, nearly one-third of weekly disposable materials are composed of yard waste, newspapers, and food waste. Many of your neighbors are sending bags of “nutrient gold” to landfills. Improve your gardening skills and save money.

Adding fallen leaves back into the garden is one of the most ecofriendly solutions that gardeners can adopt. Fallen leaves are free mulch. They’re gathered by raking, blowing, or a lawnmower with a bag attachment. A mower with a bag shreds the leaves – eventually creating a uniform leaf mold (mulch). The final product also creates a tidier look in your garden.

Put shredded leaves around the base of trees and shrubs, pile them up several inches over annual flowers or vegetable beds. A loose layer of shredded leaves can be about 3 to 5 inches thick that aids in controlling weeds. Alternatively, if you prefer the uniform darken look of store-bought mulches, start with free freshly fallen leaves as a base layer, and add a topping of purchased mulch. Over winter the fallen leaves and mulch break down and supply nutrients to the soil.

Get ahead of spring mulching chores by adding 2-3 additional inches of chopped leaves each season. October thru December is the interval when most deciduous and evergreen trees lose their leaves. Some oak and beech trees wait until late winter to lose theirs, giving rise to another wave of free mulch creation.

Mulch (composed yard waste) available at Local Garden Center

Fall leaf collecting and adding them to your compost pile greatly increases the quantity of ready for use soil conditioner in the spring. This will reduce gardening costs (think less fertilizer and lime) and improve the health of your garden plants. Oak leaves and pine needles tend to create an acidic mulch which is ideal around acid-loving azaleas, rhododendrons, mountain laurels, gardenias, hollies, to list a few.

Leaf compost provides all the nutrients that winter/early spring wildflowers such as trilliums, Virginia bluebells, winter flowering aconites, snowdrops, hardy cyclamens, and so many others need.

Empress Tree (Paulownia)

Posted by Hugh on November 26th, 2021

Empress tree (Paulownia tomentosa) is a fast-growing shade tree, in some years adding 4-5 feet of new growth, eventually to reach heights of 40-50 feet and width of 20-30 feet in less than 20 years.

Paulownia Planting at Longwood Gardens in Kennett Square, PA

In the first 3-4 years, juvenile trees develop enormous size leaves. Once trees start producing flowers (adult stage), leaves are alot smaller, although still bigger that most oaks or maples. Some gardeners create the tropical foliage appearance by cutting back young trees every 1-3 years to maintain enormous sized leaves. By doing so, they avoid flower formation which results in seeds and lots more sapling trees in the neighborhood.

Showy upright clusters of lavender flowers measure 14 or more inches across and are beautiful, although most are hidden within the bulky spring foliage. The large, velvety looking leaves resemble catalpa tree leaves.

Individual 1.5-2 inch long tube-like blooms are vanilla scented and edible. Woody brown seed capsules follow in the fall; the capsules split open to reveal winged seeds.

Paulownias are not recommended for landscape planting as they are considered short-living weedy trees. They survive in a range of soils including low fertility and high acidity sites, and either in partial to full sun. As a shade tree, it forms a wide canopy of dense shade, creating too much competition for most ground covers to survive. Paulownia is resistant to most urban air pollutants.

Insects, Diseases, and Other Plant Problems: Frost damage to early spring flower buds is possible. Plant experts rate paulownia trees as weedy, messy, weak wood and invasive species. Seed heads form in summer and the ripened seed fall in late October. According to University of Tennessee forestry experts: “some 90% of paulownia seeds are not viable, yet many states list the tree as invasive”.

In Asia, paulownia wood is manufactured into paper, veneer, hand-carvings, clogs, musical instruments, furniture, rice pots, water pails, bowls, and spoons. Some U.S. growers export the wood to Asia. It has also some medicinal uses in Asia.