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

Native Irises

Posted by Hugh on April 9th, 2023

In the World of Iris, U.S. gardeners are highly partial to planting Siberian (Iris sibirica) and German (I. germanica) irises. Currently, in recent years there has been a sway to our native species called “flag irises”.

Top of the list is Crested iris (I. cristata), a low-growing, rapidly spreading species that typically 3-6 inches tall. In the wild, crested iris is found in moist humus-rich woodsy soils from Maryland and Ohio south to Georgia and Oklahoma. Flowers have reclining standards and drooping falls. Favorite varieties are Abbey’s Violet (deep blue violet), ‘Alba’, ‘Tennessee White’, ‘Eco Little Bluebird’, and ’Shenandoah Skies’. (zones 3-8)

Northern blue flag iris (I. versicolor) is native from Newfoundland and Manitoba south to Virginia and Minnesota. This iris thrives in either wetland or terrestrial habitats. Clumps of narrow, arching-to-erect, dark purple-green foliage (to 24-inch long & 1-inch wide) emerge in early spring. In late spring, dark purple foliage gradually fades to green. Flowers arise atop 30-inch-high stalks in late spring, each stem bearing 3 to 5 blue-purple flowers (to 4-inch wide) along with bold purple veining. One to try: ‘Purple Flame’. (zones 3-8)

*Iris versicolor* ‘Purple Flame’ (photo courtesy of Mt. Cuba Center)

Southern blue flag (I. virginica) is a wetland species native to coastal locales from Virginia to Louisiana; a clump growing iris on 2 to 2.5 feet tall stems bears non-fragrant blooms with light blue to purple standards and crested yellow – white falls in late spring. ‘Contraband Girl’ is a vigorous tetraploid with blue-purple flowers and lush wide foliage. (zones 4-9)

Copper iris (I. fulva) hail from the Midwest U.S. and south into Georgia and grows in average moist soil. Flat-topped, 3-inch wide, beardless flowers form on 2-3 feet tall stalks and bear unusual rich brownish (coppery) blooms. (zones 6-9)

Slender blue iris (I. prismatica) grows in boggy soils from Maine south to Georgia. The narrow upright foliage forms rhizomatous clumps topped with lovely narrow-petaled blue-violet flowers in early May. The floral falls (petals) display a nice central whitish pattern. (zones 4-8)

Lamance iris (I. brevicaulis), native to the central U.S., grows in marshy humus-rich wet soil in full sun to light shade. It is recognized for its long zig-zag stems. Foot high stalks support 3–6 blue flags, each 1-3-inch wide and a variable range of blue -purple hues. (zones 5-9)

Rocky Mountain iris (I. missouriensis) resembles Siberian iris (I. sibirica) with narrow strap-shaped leaves to 20 inches long. Each branched stem holds 2 to 4 blooms in early summer. The beardless flowers have short, pale to deep blue or lilac-purple standards and larger falls with deep purple veining; grows in medium-wet average soil. (zones 3-8)

Available Sources:

Broken Arrow Nursery, brokenarrownursery.com

Far Reaches Farm, www.farreachesfarm.com/default.asp

Izel Native Plants, www.izelplants,com

Plant Delights Nursery, Raleigh, NC www.plantdelights.com

Red Buckeye – Delightful Small Flowering Tree

Posted by Hugh on April 3rd, 2023

Mature Red Buckeye on the ETSU Campus in Johnson City

Red buckeye (Aesculus pavia), aka Firecracker Plant, is a southeastern U. S. native that is a large understory shrub or small tree. A member of the Sapindaceae (maple) family, this lovely spring flowering beauty grows 15 to 25 feet tall in 30 years and is a perfect fit in small yards. It is native from the South-Central U.S. east thru the Southeastern U.S. (USDA hardiness zones 4-8).

Many 5- to 8-inch-long red to orange-red tubular floral panicles stand erect on branch tips in mid-spring. The vibrant colored flowers are stunningly beautiful. The glossy foliage is composed usually of five elliptical serrated leaflets palmately arranged and emerges about the same time. Within a large wild population of red buckeyes, flower color often varies from dark pink to deep red.

Red buckeye grows in average, moist, well-drained soil, and in full morning/afternoon shade or in all-day partial sunlight. The tree holds up to loads of shade although flower numbers are fewer. Spring feed with granular 10-10-10 or equivalent fertilizer. Soil moisture is of key importance as summer foliage tends to scorch during hot dry summers. In southern climes all-afternoon shade is the rule!

From late April into May, for about a month, blooms attract hummingbirds and other pollinators. Flowers are followed by three-parted smooth husks, each containing 1 – 3 shiny brown seeds within. Husk numbers vary from one year to the next.

Smooth orange-brown seed husks contain 1-3 shiny seeds (1-2- inch long nutlets). Seeds are called “buckeyes” and ripen by early fall. When husks start to split open, collect and plant ripen seeds immediately; do not allow seed to dry out. Seedling trees often start flowering in 3-4 years. Seeds are poisonous to humans and wildlife. Squirrels will collect and “plant” the seeds.

Disease and pest issues are rare, although scorched and fungal-spotted leaves tend to drop starting in late August and branches are mostly bare by the first day of autumn.

Landscape Use: good woodland or in a wildlife garden or a small specimen tree.

Insects, Diseases, or Other Plant Problems: Leaf blotch can be a problem for this plant. Leaf, stem, and fruit drop can be messy.

Cultivars: ‘Atrosanguinea’ – with deeper red flowers
var. flavescens – rare yellow form

Special Note: Often confuse with red horsechestnut (Aesculus x carnea) which is a hybrid cross between red buckeye (A. pavia) and common horsechestnut (A. hippocastanum).

Rain Lilies

Posted by Hugh on March 29th, 2023

Rain Lilies (Zephyranthes), aka Zephyr lily, fairy lily, Atamasco lily, et al. are small perennial bulbs that are native to the southeastern United States, Central and South America (USDA hardiness zones 7-10). In the U.S., these bulbous members of the Amaryllis Family (Amaryllidaceae) grow in low woods and wet meadows.

Rain lilies bloom from spring to autumn (depending on species planted). Wet to rainy summer weather is what they like. Dormant bulbs can survive hot dry spells. Soak the bulbs prior to planting for faster germination. Following the last frost of spring, sow bulbs in ground beds, rock gardens, rain gardens, or in containers @ 8-10 bulbs per sq. ft. Choose from yellow, white or pink flower colors.

Plants have grass like foliage. Depending on species, rain lilies range from 2 to 12 inches (5 – 30 cm.) in height. Sow bulbs at a depth of 3 inches (8 cm) and spacing of 4-6 inches (10 -15 cm) apart in partially shaded or sunny areas of the garden that have well-drained, moist, humus-rich, mildly acidic soil. Rain lilies benefit from fertilizing at planting time and annually.

Plant in full sun to partial shade in moist to wet organically rich soils. Occasionally add some leaf mold to the soil. It will tolerate seasonal flooding and will bloom best if it receives at least 2 hours of direct sunlight a day. This bulb is frost sensitive so only thrives in areas that do not have deep winter freezes. Northern gardeners grow rain lilies in containers as annuals and move pots into a non-freezing (cool) dry spot for winter storage.

Over the years rain lilies spread from bulb offsets to form colonies. Caution: mark the bed area as the dormant bulbs are unseen many weeks of the growing season.

Butterflies and honeybees cover blooms starting in late summer. Bulbs multiply rapidly and are both pest resistant and critter proof.

Rain lilies (bulbs) are sold by mail order suppliers and are hard to find (or sold out) at local garden shops. I recommend Brent and Becky’s Bulbs in Gloucester, VA as a mail order source.

Stop The Chop

Posted by Hugh on March 24th, 2023

Crape myrtle (Lagerstroemia indica) is a species of small, beautiful tree native to Asia, and are popular in Southern U.S. gardens (USDA hardiness zones 6-9). Before planting a tree or shrub form, do your homework first.

So many landscapes wind up with severe and senseless pruning. Crape myrtles wind up with weak shoots and poor flower numbers. Bad pruning can also delay flower development. Ask yourself: “Would you rather have a tree (good pruning) or “a living hat rack” (bad pruning) in your landscape?”

Put down the chainsaw and pick up the hand-held loppers! Crape myrtles are popular for their low-maintenance beauty, but they can benefit from some light pruning this time of year. Pruning crape myrtles to their natural shape. Tools to have on hand: small tree saw, small 5-foot ladder, lopper shears, sharp hand pruners.

According to the plant experts at Mississippi State University, here’s the
correct way to prune a crape myrtle:

· You need sharp pruning tools based on the diameter of the branches and limbs. Use bypass pruners to easily cut back branches up to 3/4 inch in diameter. For branches up to 1 3/4 inches in diameter, use a robust set of loppers. Use a pruning saw on larger branches.

· Nicely pruned crape myrtles should be multi-trunked and well-structured. Maintain an odd number of trunks, such as three or five, looks great and preserves enough space for the tree to produce strong growth.

· Remove any unwanted trunks. Cut them as close to the ground as you can. Next, choose the height where you want the branching to
start and remove lower branches back to the main trunk.

· Remove any branches that are growing into the center of the tree canopy and any crossing or rubbing limbs against each other. This creates space and opens the canopy, reducing the chance of diseases.

· Cut off seed heads to encourage more growth in the spring.

· Finish with the removal of small, thin branches. Remove any suckers that sprout up around the base. Use your hand pruners and cut these off without leaving a stub.

Dark leaf crape myrtle (‘Ebony Embers’) at Biltmore Estates

Crapemyrtles come in a variety of sizes and flower colors. Many (not all) show off an ornamental patchwork bark. Before heading to the garden center decide what flower color you want. Shop the internet or find a variety that grows (matures) to the correct height for the garden space and iss winter hardy in your plant zone. Plant crape myrtles almost any time of year with spring / summer being best and fall / winter the worse seasons. There are over 125 varieties listed on the internet. Here are 50 of the best:

Miniature/Weeping: less than 3
feet tall

Baton Rouge (red)
Mardi Gras (purple)
Pixie White (white)
Pokomoke (deep pink)

Dwarf: 3 – 5 feet tall

Centennial (purple)
Dazzle® series (GAMAD I-VII)
Petite Series (6) Pink Ruffles (pink)
Tightwad (Whit V) (red)
Velma’s Royal Delight (purple)
Victor (dark red)

Intermediate: 5 – 10 feet tall

Acoma (white)
Cheyenne (red)
Hopi (pink)
Red Rooster (PIILAG III) (rich red)
Siren Red (Whit VII) (red)
Tonto (red)
Zuni (purple)

Medium: 10 – 20 feet tall

Apalachee (lavender)
Black Diamond series (9)
Burgundy Cotton (Whit VI) (white)
Catawba (purple)
Centennial Spirit (red)
Comanche (pink)
Dynamite (Whit II) (true red)
Lipan (lavender)
Osage (pink)
Pink Velour (Whit III) (pink)
Powhatan (purple)
Raspberry Sundae (Whit I) (red/white)
Regal Red (red)
Seminole (pink)
Sioux (pink)
Tuskegee (pink)
Yuma (lavender)

Tall: more than 20 feet tall

Arapaho (red)
Biloxi (pink)
Byers Hardy Lavender (lavender)
Byers Standard Red (red)
Kiowa (white)
Miami (pink)
Muskogee (lavender)
Natchez (white)
Potomac (pink)
Red Rocket (Whit IV) (true red)
Sarah’s Favorite (white)
Townhouse (white)
Tuscarora (pink)
Watermelon Red (red)
Wichita (lavender)

Growing Crapemyrtles In Containers

Posted by Hugh on March 17th, 2023

Gardeners who live in USDA zones 6 -10 can grow dwarf (shrubby) crapemyrtles either in the ground or in containers. In northern areas of the U.S., a few crape myrtle varieties are tender perennials and grown in containers. They’re overwintered in an unheated garage, shed or pots are dug into the ground.

These dwarf varieties are designed for mass planting, low hedging and screening, and in containers. I’ve identified 12 varieties that perform in garden beds or containers:

‘Pocomoke’ – features bright pink blooms and deep green foliage on a mounding shrub (3 – 5 feet high & 3 – 4 feet wide). (Zones 6-9)

‘Berry Dazzle’ crapemyrtle (red seed capsules)

‘Razzle Dazzle’ Series – mounding 3 to 4 feet tall and wide shrub form. The hardiest performers in the series are ‘Cherry Dazzle’ (red blooms) and ‘Berry Dazzle’ (fuchsia-purple blooms/ burgundy new foliage). (Zones 6-9)

‘Tightwad Red’ (Whit V) – produces dark-red flowers on a mounding plant (3-4 feet tall & 5-6 feet wide) with dense foliage. No seed capsules are formed. (Zones 7-10)

‘Victor’ – bears deep red flower with a narrow shrub form (3-6 feet tall & 2-4 feet wide). (Zones 6-9)

Barista® series (7 varieties) from Walters Gardens will grow 2 – 3 feet in height and width. Plants are rated hardy perennials in zone 5-6 and dieback to the ground. Plants re-emerge in the spring in Ohio, Illinois, and Michigan. They bloom on new wood in mid-late summer. In warmer climes Barista varieties do not die back in winter and their mature heights will be taller. (Zones 6-9)

Containers should be set in full sun and moderately watered. Once established after their first year, feed with a water-soluble fertilizer such as Miracle-Gro™ or Peters™ every 4-6 weeks. Do not fertilize after late summer (September 1).

In zone 5-6 winters, move container grown plants into an unheated garage or shed where temps won’t drop below 20 °F. Otherwise, backup with supplemental heating. Water plants once every 3-4 weeks. An alternative approach is to submerge pots outdoors in garden soil and heavily mulch in a heap of loose, non-packing leaves and pine needles. Push the leaf litter aside after the worse of winter low temps has left your geographic area. Re-cover with leaves during sudden temperature dips. In spring carry tender Barista crape myrtles back outdoors and resume regular watering and fertilizing.

‘Ogon’ Spirea Is A Standout

Posted by Hugh on March 12th, 2023

Spireas (Spiraea spp.) represent a large number of mostly non-native flowering landscape shrubs. Most are not U.S. natives, indigenous to China and Japan. Baby’s breath spirea (S. thunbergii) is also called Thunberg spirea and Breath of Spring spirea. It is a showy, graceful shrub that grows 3 to 5 feet high and wide with many slender, arching branches (USDA hardiness zones 4-8).

One of the popular cultivars is Golden Thunberg (S. thunbergii ‘Ogon’). This spirea is one tough tough plant. Its abundant flowers and gold leaf color is stunningly beautiful. Tiny white flowers cover the shrub in late winter to early spring before the leaves appear. Narrow, willow-like, sparsely toothed leaves (to 1.5 inches long) emerge golden yellow in spring, transition to chartreuse green in summer and turn interesting shades of orange to yellow in autumn.

‘Ogon’ is an exceptional golden-leaved cultivar best grown in full sun to retain its lovely golden foliage over almost three-seasons. It prefers moist well-drained soils and becomes more drought tolerant as the shrub ages. Pruning is best performed immediately after the spring blooms have faded. Annual pruning helps to maintain the shrub’s shape and appearance. Rabbits and deer are not usually troublesome.

It may be used as a hedge, screening, or windbreak. It may also be considered as a foundation, border planting, or specimen.

Baby’s breath spirea grows in a wide range of soils, medium moisture, well-drained soils and in full sun. The shrub tolerates light shade, and moderate drought. Prune as needed immediately after flowering to maintain shape.

Ogon spirea is rarely troubled by disease or pest problems that plague other members in the rose family including leaf spot, fire blight, powdery mildew, root rot, aphids, leaf roller and scale.

Caveat: Do not confuse this plant with gold mound spirea which is Spiraea japonica ‘Goldmound’.

False Solomon Seal

Posted by Hugh on March 7th, 2023

False Solomon’s seal (Maianthemum racemosum) is a native woodland plant. It earns its common name because it looks very similar to Solomon’s seal (Polygonatum spp.). Both are in the lily family (Liliaceae) and are often seen growing together and easy to distinguish apart by the placement of the flowers on the plants.

Formerly classified Smilacina racemosa, this plant that ranges across most of North America north of Mexico in zones 3-9. Biologists reclassified to the genus Maianthemum a long time ago but is often listed by its old scientific name. Native Americans used the root and leaves medicinally and ate the young shoots and processed roots.

It is an herbaceous perennial, e. g., the foliage dies down to the ground in autumn and re-emerges in spring from the stout, fleshy, persistent rhizomes with secondary fibrous roots. The alternate, ovate leaves are produced on 1–3-feet high arching stems that stand tall well into summer. The slightly hairy, reddish or green stems zigzag slightly between the leaves.

Each smooth, entire leaf measures up to 6 inches long with prominent parallel veins lengthwise. The foliage may turn yellow to gold in the fall but sometimes just goes brown. Over time vigorous plants may form large colonies from slowly spreading clumps.

Flower clusters can form between 20 and 80 individual flowers. Each ¼ inch wide star-shaped flower is comprised of 6 tepals (petals and sepals that look the same), 6 stamens with yellow anthers and a solitary central pistil. Flowers are very different from the bell-shaped flowers of Solomon’s seal that hang from nodes along the stem.

Late summer leaf color and red fruits (*Maianthemum* *racemosu*m)

In late spring and early summer feathery masses of small white to pale yellow, fragrant flowers are produced in flat panicles at the ends of the stems. The flowers are followed by clusters of small berries, each containing a few seeds. They turn from green (or green with purple speckles that gives an overall appearance of a russet color), to translucent red or red and purple-marked when they ripen in late summer or fall.

The berries of False Solomon’s seal are reportedly edible and also are red according to some other sources. Flowers are pollinated by small bees, flies, and beetles. Birds and field mice forage the berries and disperse the seeds to other areas of the property.

Blue Flowering Shrubs

Posted by Hugh on March 1st, 2023

Most associate the color BLUE with the sky, the sea, and an endless horizon. Blue colors evoke feelings of tranquility, calm, and a peaceful state of mind. “Blue Skies” brings out happiness and smiles in people, particularly after consecutive days of dreary weather. Contrarily, a blue mood may elicit feelings of sadness and depression.

The BLUE color spectrum ranges between violet and cyan. In the gardening world few shrubs produce blue flowers, most in the pale blue to lavender range. Below are nine (9) of the best “blues” in the world of shrub flower world.

Bluebeard (Caryopteris x clandonensis), aka blue mist shrub, blooms in late summer into autumn on this 2-3 feet tall shrub (zones 5-9). Cultivars: ‘Longwood Blue’, ‘Beyond Midnight’.

Rhododendron (Rhododendron spp.) cultivars produce numerous lavender blue flowers. Popular varieties include: 1. many catawba rhododendrons (Rhododendron catawbiense) produce lavender-pink flowers from April to early June (zones 4 to 8); 2. PJM rhododendron (Rhododendron x ‘PJM’), bears lavender-pink flowers in early April (zones 4-8); 3. ‘Blue Diamond’ and ‘Blue Baron’ are compact 3 foot high hybrid cultivars bearing blue-lavender flowers in late spring (zones 7 – 9).

Common Lilac (Syringa vulgaris) are available in several color shades of lavender, blue, reds, and white. One of the almost blue cultivars is S. hyacinthiflora Scentara^® with double blue blooms (zones 2-8).

Butterfly bush (Buddleia x) is a subshrub. ‘Blue Heaven’, ‘Blue Chip’, ‘Blue Knight’ are among a long list of blue-flowered buddleias; depending on cultivar grow 5-12 feet high and some even taller (zones 5-9).

Bigleaf Hydrangea (Hydrangea macrophylla) produces huge mophead flowers in summer on 3 to 4 feet tall plants in full sun to partial shade, depending on where you garden. Best blue cultivars: ‘Nikko Blue’, ‘Nantucket Blue’, Endless Summer™ series, Let’s Dance™ Blue Jangles, Let’s Dance™ Rhythmic Blue. (Zones:5-9).

Rose of Sharon (Hibiscus syriacus) is an old-fashioned 8 to 12 feet tall shrub with lacy blooms from summer to fall. Blue cultivars: ‘Blue Bird’, ‘Blue Chiffon’, ‘Lavender Chiffon’ (Zones 5-8).

Lavenders (Lavandula spp.) is a perennial subshrub treasured for their floral beauty and fragrance and also purposed for culinary, medicinal, and decorative potpourri. Select from blue-purple flowered ‘Mumstead’ English Lavender (L. angustifolia) (zones 5 – 8) and some French / Spanish lavender (L. stoechas) varieties (zones 7b-9).

Chaste Tree (Vitex agnus-castus) is a 6-12 foot tall shrub or 12-16 foot small tree. Cultivars: dwarf: ‘Blue Diddley’ and ‘Blue Puffball’ grow 3 – 6 feet tall; ‘Shoal Creek’ (12 feet tall).

California Mountain Lilac (Ceanothus ‘Concha’) bears purple or blue flowers that are highly fragrant (Zones 7 -10).

All About Flowering Quinces

Posted by Hugh on February 22nd, 2023

Flowering Quince (Chaenomeles speciosa) is a deciduous shrub in the Rose (Rosaceae) family and related to apple and pear (Zones 5-9). It is native to China and is relatively easy to grow. Plant quince in moist, well-drained soil; it flowers best in full sun but is moderately shade tolerant. Feed quince shrubs annually in early spring before new growth emerges with a slow-release fertilizer.

Flowering quinces offer multi-seasonal interest. Red, orange, pink, or white flowers (depending on variety) appear around the same time as spring crocus, hyacinths, and early tulips are also beautifying gardens. Flowers are glorious over 10 to 14 days. Blooms, as large as 1.5 inches in diameter, either appear singly or in clusters of 2-4. Several months later, the 2.5 inch long yellow-green quince fruits ripen.

Harvest fruits when they turn from pale green to yellow; they’re usually too hard to eat raw and bitter tasting. Harvest them and bring indoors to ripen. Fruits bruise easily. Store quinces on trays, not touching each other, in a dark, cool spot for 6-8 weeks before using. Also store quinces away from apples. Quince fruits soften with cooking, making tasty preserves and jellies or eat after fully ripened.

Pruning occurs after spring flowering to shape the shrub, to remove old dense wood, including all diseased and dead wood, and to stimulate the growth of flowering spurs for the next year. Be careful of their dense spiny wood.

C. speciosa is a tough, hardy plant that would make a great informal hedge. It is moderately salt-tolerant, and in comparison, C. speciosa grows more upright than its relative C. japonica. In general, quinces dislike high pH (alkaline) soils.

Quinces are easy to transplant. Pest and disease problems need to be considered, particularly on old fashioned varieties which were susceptible to fire blight. Modern day cultivars are highly resistant to fire blight disease. Aphids can be a problem on stressed plants.

Double Take series: ‘Scarlet Storm,’ ‘Orange Storm,’ and ‘Pink Storm’ grow to 5 feet high with double flowers of scarlet, orange, or pink. Branches are covered with blooms. Shrubs are shorter overall, do not produce fruits, and are largely thornless. Early arriving butterflies and hummingbirds will visit the early flowers.

Older varieties such as Super Red, Toyo-Noshiki, and Texas Scarlet are spotted in older landscapes as tall 8-10 feet hedges. Beware of their sharp barbed thorns.

Alternative: C. japonica grows only 2-4 feet tall with salmon to orange-colored flowers outward.

Varieties Of Crape Myrtles

Posted by Hugh on February 18th, 2023

Crape myrtles (Lagerstroemia x indica) are small flowering trees and shrubs that are native to Asia and have naturalized in the Deep South of the U.S. Back in the 1970’s thru the 1990’s, plant breeders at the U.S. National Arboretum released 35 winter hardy varieties, named after North American Indian tribes. They varied in sizes ranging from 5-foot shrubby rose-pink flowered ‘Pocomoke’ to 30-foot white flowered tree ‘Natchez’. The U.S. nursery industry followed up with 100 more varieties that fit in most landscape designs.

‘Natchez’ Crape Myrtle (25-30 feet category)

Crape myrtles come in a variety of tree or shrub sizes and flower colors. Many (not all) show off an ornamental patchwork bark. Before purchasing, select a variety based on mature tree/shrub size, flower color, and ornamental bark. Shop the internet or local garden center to find a hardy variety that fit into the garden space.

Plant a crape myrtle any time of year, from early spring to late summer and no later. More than 125 varieties are listed on the internet. Here are over 60 of the best arranged according to their mature height:

Miniature/Weeping: less than 3 feet tall