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

Flowering Shrubs of Summer

Posted by Hugh on August 7th, 2017

Rose of Sharon (Althea)

Plumleaf azalea (close-up)

In several areas of the U.S. (USDA hardiness zones 6-9), summer landscapes along the east and west coast and Southern U.S. are filled with these botanical beauties:

Panicle hydrangeas (Hydrangea paniculata) – so many great choices of these hydrangeas, mostly with lime white flowers starting in July into August. Most popular cultivars are ‘Limelight’, ‘Little Lime, ‘Quickfire’, ‘Vanilla Strawberry’, ‘Diamond Rouge’, ‘Bobo’.

Bigleaf hydrangeas (Hydrangea macrophylla) – Bloomstruck® series, Endless Summer® series, LA Dreamin®, ‘Nikko Blue’, Lets Dance® Diva collection are among the winter hardiest to date

Chastetree (Vitex agnus-castus) -10-15 feet shrub in color choices ranging from purple (also lavender, pink and white) blooming; new dwarf 5-8 feet cultivars are coming to garden centers in near future. The current popular forms are ‘Shoals Creek’, ‘Montrose Purple’ and ‘Woodlander’s White’.

Summer sweetshrub (Clethra alnifolia), aka sweet pepperidge is an absolute bee favorite in my garden. Popular cultivars include ‘Sixteen Candles’, ‘Rosea’, and ‘Hummingbird’.

Flowering abelia (Abelia x grandifolia) – choose old-fashioned shrubs @ 12-15 feet;, modern compact cultivars at 4-6 feet such as Rose Creek®, ‘Mardi Gras’, Canyon Creek®,and ‘Ed Goucher’; low growing types 2-3 feet bsuch as Kaleidoscope®, ‘Confettii’, ‘Sherwood’ .

Altheas or Rose of Sharon (Hibiscus syriacus) -choose from Chiffon® series, ‘Blue Bird’, Roman Goddess series from U.S. National Arboretum (Aphrodite’, ‘Minerva’, ‘Diana’, and ‘Helene’).

Crape myrtles (Lagerstroemia x) – white, pink, rosy-pink, lavender, and red crape myrtles; available to four size catergories: tree (26-30 feet), intermediate (13 -20 feet), semi-dwarf (5-12 feet), and dwarf (3-5 feet).

Bluebeard shrubs (Carypteris x clandonensis) – small 2-3 feet high compact shrub that bloom from mid-summer into fall . Select cultivars ‘Dark Knight’, Longwood Blue®, Beyond Midnight®, Grand Bleu®, and Petite Bleu®; also gold leaf ‘Worcester Gold’.

Blue Mist shrubs (Caryopteris divaricata) – taller growing @ 4-6 feet and also bloom from late summer into fall; select from Snow Fairy® and ‘Blue Butterflies’.

Caryopteris divaricata ‘Snow Fairy’ at Biltmore Estates in Asheville, NC

Additional choices available from specialty nurseries include plumleaf azalea (Rhododendron prunifolium) and butterfly bush (Buddleia davidii) that bloom through most of the summer into autumn.

Comparing Encore™ and Bloom-A-Thon™ Azaleas

Posted by Hugh on August 4th, 2017

Rhododendron ‘Encore Autumn Rouge’ in late August

‘Bloom-a-thon Lavender’ at Biltmore Estates

Hey gardeners, how about azaleas that bloom nearly 5 months a year. Flowering lasts for 4-6 weeks in spring and another 12-16 weeks in summer and fall. Check out Encore™ and Bloom-A-Thon™ series of azaleas (USDA hardiness zones 6-10).

The main differences between these two azaleas is the Bloom-A-Thon series tend to bloom more abundantly in shaded sites and foliage and flowers will burn in full direct sunlight in hot parts of southern U.S. (zones 7b-10). The Encore series are bred to bloom in full sun and bloom less in shaded areas. The Bloom-A-Thon series tends to be more cold hardy for zones 6-9. Encore is hardy in zones 7-9 with nine or more cultivars winter hardy in zone 6 as well. Encore azalea come in lots more color choices.

To repeat, the Encore™ azaleas tolerate more direct sunlight and prefers 4 to 6 hours of direct sun; give them some afternoon shade in warmer climes. Bloom-A-Thon™ prefers part sun to dappled shade; too much direct sunlight may scorch flowers, particularly in the summer sun.

Bloom-A-Thon at this time only are available in four cultivars (red, white, lavender, and double pink). Growth height and width vary with the white cultivar (smallest) at 24 to 36 inches tall and wide and the lavender cultivar (tallest) at 60 to 72 inches tall and wide. Encore azalea series now includes 31 varieties with many different single and double flowers with many color choices.

General care: Water azaleas deeply at planting and keep garden and container soils moist into late fall. Established 1 year and older plants are generally moderately drought tolerant unless summer weather is unusually droughty. Fertilize according to recommended package directions for azaleas of popular brands of water soluble products such as Miracle-Gro™, Peters™ or Espoma™. Do not fertilize after early September. Pruning, if needed, in early spring is usually light, primarily to remove any dead or damaged wood and to shape and size the shrub.

Hard Working Perennials For Your Late Summer Garden

Posted by Hugh on August 1st, 2017

Mexican sage (Salvia leucantha)

New England aster

Add several fall-flowering perennials to your garden that will add late season color and pizzazz . These are reliable tough perennials, and beneficial pollinators love them. Visit garden centers in August to make your purchases.

However, for these great plants to return next year and subsequent years, plants need to get their root systems established. Have plants in their permanent garden spots by mid-August if you garden in northern climes. Most are hardy in zones 5-9.

Check out these hardworking perennials for a great autumn floral finish.

Tame goldenrods (Solidago x spp.) such as (S. rugosa) ‘Fireworks’ or (S. sphacelata) ‘Golden Fleece’ are garden-winning classics.

Fall blooming asters like New England (Symphyotrichum. novae-angliae) and aromatic asters (S. oblongifolius). There are lots of great cultivars.

Fall sunflowers (Helianthus spp.) – these are the perennial kinds like (H. angustifolius ‘Lemon Queen’), willowleaf (H. salicifolius), H. x multiflorus ‘Sunshine Daydream’ or hybrid cultivars like Helianthus x ’Lemon Queen’.

Hardy Plumbago (Ceratostigma plumbaginoides) is a low growing (ground cover) that starts blooming in August into autumn those blue flowers provide an unexpected pop of color as the rest of the landscape fizzles.

Pitcher Sage (Salvia azurea) is a Central U.S. native that grows in a variety of soil types. Russian Sage (Perovskia atriplicifolia) is mostly bloomed out by late summer unless properly deadheaded(zones 5-9). Blooming in late summer and early fall, pitcher sage is admired for its sky blue flowers and high drought tolerance. This salvia grows to 30 to 36 inches in height, but may be pinched back for bushier growth.

Mexican sage (Salvia leucantha), zone 7 hardy, is a fall-flowering perennial often at full-tilt as cooler temperatures set in.

Many kinds of stonecrop sedums come in a variety of sizes such as ‘Autumn Joy’, Dazzleberry® series, and ‘Matrona’.

Fall anemones (Anemone x) come in shades of white, lavender, and pink in full sun to partial shade.

The Ornamental Grasses:

Maiden hair grasses (Miscanthus sinensis) are beautiful in the early autumn landscape. Cultivars such as ‘Adagio’, ‘Rigoletto’ and ‘Morning Light’ are rated as less invasive types.

‘Northwind’ switch grass (Panicum spp.) offer long panicles of feathery flowers. Pink or white muhly grass (Muhlenbergia capillaries) display colorful billowy inflorescenses.

Little blue stem (Schizachyrium scoparium) are popular native warm season grasses; many varieties tend to lodge (fall apart) late in the season. ‘Standing Ovation’, a new variety, doesn’t fade or flop as temperatures drop off into winter.

Pest Alert – Crape Myrtle Bark Scale

Posted by Hugh on July 28th, 2017

Crape myrtle bark scale (Photo by Dr. Frank Hale, UT Entomologist, Nashville, TN)

Crape myrtle bark scale (photo by Dr. Frank Hale, Univ of Tenn. Extension Entomologist)

A new scale has been observed infesting crape myrtles (Lagerstroemia x indica) in north Louisiana and Texas cities. In the summer of 2016 it was found threatening crape myrtles in the Piedmont area of North Carolina and in west Tennessee (Memphis). Crape myrtle bark scale is a felt scale related to azalea bark scale and oak eriococcin scale. (Eriococcus lagerostroemia). It feeds on plants in Japan and China.

Female scales produce fluffy white filaments that cover their bodies. In spring they produce eggs beneath their body then die. Tiny crawlers hatch from the eggs, settle in their new spot, and begin producing white filaments. They have at least 2 overlapping generations. At low density, crape myrtle bark scale feeds in rough areas around branch collars but as the population increases all the bark may be covered. These scales are most often noticed because trees become covered in black sooty mold. At first many people assume this is from crape myrtle aphids and the scales may go undetected. If you notice unusually heavy honeydew and sooty mold on crape myrtles take a closer look at the bark.

This pest excretes honeydew that coats leaves and limbs, resulting in a sticky coating from the excess sugars excreted from the insects’ feeding. Sooty mold grows on the honeydew. This results in a black (sooty mold) coating that appears on the bark of the branches and trunks of crape myrtles. Additionally, white cases are visible, and they enclose the adult female scales.

Insects appear as white, waxy encrustations likely to occur anywhere on the plant but often near pruning wounds or in branch crotches. Up close, the bark scale insect is white to gray in color. Larger female scales “bleed” a pink liquid when crushed. Crape myrtle scale appears pink in color inside the case. Careful examination may reveal dozens of pink eggs under some of the larger white scale covers.

Recommendations for managing the scale are still being developed; however, current management suggestions for this scale include:

Wash the trunk and reachable limbs of heavily infested plants with a soft brush and mild solution of dishwashing soap. The egg masses and female scales will be washed off, resulting in improved effectiveness of insecticides. Also, the black mold building up on the bark of infested trees will be removed by washing. The scales and sooty mold may be removed by using water pressure. Removing the loose bark is important because the protected areas where the scales hide are removed. This removes the areas that the scales may use for protection from unfavorable weather in winter.
First application should be made between May and July with follow-up applications every 3-4 weeks as needed. Systemic insecticides include dinotefuran (Safari™) and imidacloprid (Merit™ or Bayer Advanced Garden Tree and Shrub Insect Control™). Drench applications of neonicotinoids are typically effective against phloem feeders. Read the labels for restrictions on using neonicotinoid pesticide as crape myrtle flowers attract multitudes of beneficial pollinators. Horticultural oil, especially the heavier dormant rate, can also reduce scale numbers.

If you find this scale on your crape myrtles, take a sample to the local Extension office for identification.

Credit: information for this blog supplied by the Extension Services of Louisiana State University in Baton Rouge and University of Tennessee in Knoxville.

Pineapple Lilies For Summer Garden

Posted by Hugh on July 25th, 2017

Eucomis comosa ‘Oakhurst’

E. comosa ‘Sparkling Burgundy’

Pineapple lilies (Eucomis spp.) are native of South Africa and are easy to grow (USDA hardiness zones 7-10). Several hybrid cultivars are winter hardy in zone 6 if provide a protective layer of mulch or loose leafy compost.

Plants have basal rosette of strap-like, wavy-edged, purple-spotted, dark green leaves which spread upward and outward to 24 inches. Leaf color varies with the cultivar. Emerging from each rosette is a thick purple-spotted flower stalk to 36 inches in height in mid to late summer bearing masses of tiny, starry, greenish-white flowers, also cultivars with dusky purple shades. Their unique flowers are crowned by a tuft of greenish leaf-like bracts.

Grow pineapple lilies in containers or in a garden bed with flowering perennials and annuals. Plant bulbs 6 inches deep in fertile, well-drained garden soil and in full sun. Shade will reduce flowering and bloom stalks are weak and require staking. Space plants 18-36 inches apart depending on the vigor and size of the cultivar. Pineapple lilies perform best if dry during winter dormancy.

In spring or at planting, apply a granular 10-10-10 or equivalent fertilizer or a slow release product such as Osmocote® or Nutrikote®. Keep plants well-watered during their first growing season for optimum flowering.

Plant in a wide container in loose porous soil-less media. Space bulbs 5-6 inches apart for a striking display. Place the top of the bulb is just below soil surface. Keep well-watered during the growing season (April to early October) and feed with a water soluble fertilizer such as Miracle-Gro®, Peters®, or Schultz®.

In colder regions pineapple lilies are ideally grown in containers and over-wintered indoors. Set in a freeze-free place and allow soil to dry out and bulbs to go dormant. Remove withered dead foliage. Begin watering again in late March or April.

Leading Cultivars:

‘Sparkling Burgundy’ – dark burgundy spring foliage that gradually turns olive green, and its burgundy color returns in early fall; smoky pink florets stand on 20- to 30-inch floral stalks crowned by tufts of purple bracts (zone 6b – 10).

‘Oakhurst’ – narrow leaves start off green and gradually develop an intense burgundy-red color; 18- inch tall smoky red floral stalks open pink with tufted top (zone 7 – 11).

Distyliums Substitute For Cherry Laurels and Hollies

Posted by Hugh on July 22nd, 2017

Distylium ‘Cinnamon Girl’

‘Emerald Cascade’ distylium

Distyliums (Distylium x), aka Isu tree, are being billed as “the best new plants you’ve never heard of”. Get accustomed to seeing these boxwood-like shrubs in local garden centers, e.g., if you live within USDA hardiness zones 6b-9. Distyliums are the result of selective breeding efforts to improve an evergreen shrub native to China at elevations above 3000 feet.

Hybrid distyliums are heat and drought tolerant and cope with wet soils. Their foliage is highly disease and insect resistant. They are an excellent replacements for those evergreen shrubs susceptible to one or more disease and pest problems. Examples include euonymus (Euonymus fortunei), cherry laurels (Prunus laurocerasus), junipers (Juniperus spp.), hollies (Ilex spp.), and Indian hawthorn (Rhaphiolepis spp.).

Distyliums perform best in full to partial sunlight and in moist well-drained soil. Shrubs thrives in moist, well-drained, slightly acidic soil; do not plant on poorly drained site. Keep plants mulched for a mostly weed-free planting and to conserve soil moisture. Feed with a slow release fertilizer such as Osmocote® or Nutrikote® at the start of spring. Prune after flowering to size and shape shrub.

These five cultivars are all hybrids (D. myricoides × D. racemosum):

Vintage Jade® grows in an arching mounding form low and spreading at 2-3 feet high and 5 feet wide, ideal low hedges and borders along walkways or paths.

Cinnamon Girl® has bronze foliage at 3 feet tall and 5 feet width. plum-purple new growth which turns blue-green as the leaves and mature to blue green.

Blue Cascade® grows slightly upright at 3 feet high and 4 feet wide with dusty bluish cast to the foliage.

Emerald Heights® has dark green glossy foliage and slightly upright form at 5 feet high and wide.

Coppertone® 3-4 feet evergreen shrub with a rounded to spreading habit. New leaves are coppery red mature to blue green.

Distyliums belong to the witchhazel family (Hamamelidaceae). Small, reddish maroon flowers bloom in March and go pretty much without notice. They make wonderful foundation, screening and hedging shrubs in almost any landscape. Add them to mixed plantings in large containers.

Four Top Rated Coreopsis You Should Know About

Posted by Hugh on July 19th, 2017

Coreopsis ‘Gold Standard’ (photo by MT Cuba Center)

Coreopsis ‘Last Dance’ (Photo by MT Cuba Center)

Coreopsis (Coreopsis spp.) are flowering perennials (and annuals) native to the eastern U.S. In 2016, MT Cuba Center* in Greenville, Delaware reported on the overall garden performance of 13 species and related cultivars and hybrids in the Mid-Atlantic region. Over a period of 3 years, the MT Cuba staff evaluated habit, floral display, disease resistance, and longevity. Several popular cultivars performed poorly because of disease susceptibility and winter survivability.

Four underutilized native species and cultivars earned outstanding performance ratings. All four also displayed excellent resistance to powdery mildew, downy mildew, and leaf spot diseases.

‘Summer Sunshine’ coreopsis (C. palustris ‘Summer Sunshine’) is the highest-rated coreopsis in the 3-year trial. Vigorous mounds of foliage grow to 30 inches tall and remain lush, sturdy, and dense all season long. In late September plants are covered with golden yellow flowers with dark central cones. The amazing display lasts for six weeks, and provided an important late-season food source for pollinators. ‘Summer Sunshine’ is a rhizomatous selection that slowly increases in size by 2.5 feet over three years.

Coreopsis ‘Flower Tower’ (photo by Mt Cuba Center

‘Flower Tower’ coreopsis (C. tripteris ‘Flower Tower’) appropriately named, towers over the competition at an astonishing 8 feet tall. Stems are thick and sturdy and capable of staying vertical in even the strongest winds. It is the tallest coreopsis in the trial, and also has the largest flowers, measuring 2½ inches across. ‘Flower Tower’ is perfect for large-scale landscapes, perhaps not in average sized gardens. This rhizomatous selection spreads very slowly, about 2 feet over three years.

‘Gold Standard’ coreopsis (C. tripteris ‘Gold Standard’) is another superior selection that typically grow to 7 feet tall, with a floppy habit and uninspiring floral display. ‘Gold Standard’ is a slightly shorter (5½ feet tall) and has incredibly sturdy stems. By late July, a multitude of sunshine yellow flowers appear above the robust foliage in mid-August and the floral display lasts over two months. ‘Gold Standard’ has a rhizomatous habit and spreads slowly (about 2 feet over 3 years).

‘Last Dance’ coreopsis (C. integrifolia ‘Last Dance’) is a fall-blooming tickseed whose uniformly compact habit is a vast improvement over other versions of C. integrifolia. ‘Last Dance’ is slow to emerge in the spring. It often does not reach 1 feet tall until June, and eventually tops out at only 2 feet tall. The 2 inch, extra-large, golden flowers have strongly pleated petals which make them look thick and substantial. ‘Last Dance’ is the last tickseed to flower, blooming throughout October. ‘Last Dance’ spreads via rhizomes at a rate of about 12 inches per year.

*Blog readers are encouraged to read the entire Coreopsis Report on the Mt Cuba website.

Don’t Totally Dislike All Box Elder Trees

Posted by Hugh on July 16th, 2017

Foliage of ‘Kelly’s Gold’

A. negundo ‘Falmingo’

Box elder (Acer negundo) is a native fast-growing and suckering medium-sized tree (USDA hardiness zones 4b-8). Branches are weak wooded and easily damaged in wind and ice storms. Box elder grows almost anywhere in any average soil, medium to wet, and in full sun. The species fails on a shady site. This weedy maple is tolerant of drought and flooding, perfect choice in fence rows, abandoned fields, and in vacant urban lots.

A mature tree typically grows 30-50 feet tall with an irregular rounded crown. Flowers and leaves emerge from mid-April to late May, depending on region of the country. Dioecious trees, either male or female, bear yellow-green wind-pollinated flowers in mid-spring. Compound foliage comprised of 3-5 leaflets. Non-showy flowers appear in pendant clusters in spring on separate male and female trees. In late summer winged nutlets (samaras) ripen on female trees and often hang on well into winter. Seedlings will likely become a nuisance weed in gardens. Fall color is often a blah yellow but in some years may surprise.

Box elder is a high maintenance tree. The tree is plagued by boxelder bugs, which do not harm the tree but can be a serious nuisance pest to homeowners as bugs invade houses in fall and winter months. Tree is also susceptible to aphids and borers. Anthracnose, powdery mildew and canker are occasional disease problems. Planting it in some cities is illegal. There are lots of better trees to choose from.

Cultivars have been developed with variegated or colorful foliage, improved plant habit, and better fall color. These 5 cultivars are mostly available from on-line nurseries:

‘Flamingo’ – 30-35 feet tall, variegated leaves (light green, with white and pink), a male clone (seedless).

‘Kelly’s Gold’ – 15-20 feet tall, bright yellow new growth, a male clone (seedless).

‘Sensation’ – 30 feet by 25 feet tree, reddish foliage in fall, a male clone (seedless).

‘Variegatum’ – 40 by 25 feet tree, variegated leaves (white margins), a female clone.

‘Aureomarginatum’-small 30 foot tree with dark green/white variegated foliage, female clone.

Thistle-like Bear’s Breeches

Posted by Hugh on July 13th, 2017

Acanthis spinosa at Kingwood Center, Mansfield, Ohio

Archiecturally beautiful flowers

Spiny bear’s breeches (Acanthus spinosa) is a clump-forming perennial treasured for its attractive thistle-like foliage and architecturally bold flower spikes (USDA hardiness zones 5b-9). Plant requires little maintenance and is long-lived. Deeply-cut, arching, glossy green, spiny, thistle-like leaves attain 2-3 feet in length on older plants and remain attractive through the growing season. Leaves bear mostly hidden spines on the tip of leaf lobes.

In late June through July (in zone 7), wands of hood-bracted flowers stand upwards of 2 feet above the dark green foliage mound. White-lipped blossoms expose purple (mauve) calyces. Foxglove–like flowers vary from white, pink or purple and attract lots of bees.

Good soil drainage is absolutely essential. Bear’s breeches is easily grown in average medium soil in full sun to part shade. The plant lingers or fails on poorly drained sites. In richly organic soil, plant mounds may reach 3-4 feet tall and wide. Plants tolerate considerable shade, but at the expense of flower numbers.

Foliage needs some afternoon shade in southern U.S. hot summers (zone 7-9). Over the years bear’s breeches will aggressively spread by underground rhizomes. Additional seedlings may pop up from the mother plant. In the early years it establishes slowly in the garden. Older clumps may be difficult to eradicate; new shoots can sprout if a small section of root is left behind.

Bear’s breeches has no serious insect or disease problems. In wet summers snails and slugs cause considerable damage to the foliage if left unchecked. The showy flowers are long lasting in cut floral arrangements. Be wary that each flower harbors a tiny sharp spine. Deer and rabbits generally stay away from this spiny plant.

Bear’s breeches (A. mollis), also indigenous to Southern Europe, bears softer spines, and is not as cold hardy as its spinier cousin (A. spinosus). Protect A. mollis from afternoon sun.

Best of MT Cuba Center 2017 Monarda Study*

Posted by Hugh on July 10th, 2017

Monarda ‘Jacob Cline’

M. didyma ‘Violet Queen’

Monarda, commonly known as bee balm or wild bergamot, is a popular summer flowering perennial. Their large, brightly colored flower clusters brighten the season. Flowers attract many types of wildlife, including hummingbirds, bees, butterflies, moths, and seed-eating birds. Unfortunately, many cultivars are susceptible to powdery mildew disease which causes defoliation and plant loss.

Over the past three years, MT Cuba Center in Greenville, DE evaluated the performance of 40 selections of bee balm. Staff assessed their overall garden performance in the mid-Atlantic region. Particular attention was given to plant habit, powdery mildew resistance, leaf retention, and flower coverage. There found no perfect bee balms. However, several cultivars are worth mentioning.

Monarda fistulosa ‘Claire Grace’ ranked high in the trial due to its sturdy, upright habit and prolific floral display. Compared to species, ‘Claire Grace’ has a sturdier habit, darker purple flowers, better resistance to powdery mildew, and more attractive, glossy green foliage.

Monarda ‘Dark Ponticum’ stood out in the trial for its incredibly healthy-looking foliage. The dark, bluish green leaves give the plant a very lush and attractive appearance throughout the entire season. Powdery mildew can occur but does not affect foliage health of the foliage. Violet-purple flowers attract lots of bees.

Monarda ‘Violet Queen’ is a prolific bloomer and a bee favorite. Flower color is similar, though slightly lighter than ‘Dark Ponticum’. ‘Violet Queen’ has short, silvery leaf hairs which give the leaves a dull green appearance comparable to M. fistulosa.

Monarda ‘AChall’ (Grand Marshall™) has gorgeous, deep red-purple flowers, a compact habit (28 inches tall), and excellent powdery mildew resistance. Growth habit is very uniform and plant spreads slowly.

Monarda ‘Judith’s Fancy Fuchsia’, ‘Colrain Red’, and ‘Raspberry Wine’ are all very similar in habit, flower color, and performance. Of the three, ‘Judith’s Fancy Fuchsia’ displays better disease resistance. Plants bloom 44 – 48 inch tall with abundant large, purplish red flowers in early July. Floral production is identical among all 3 cultivars, each producing 80% flower coverage at peak bloom.

Monarda ‘Purple Rooster’ has the darkest, truest purple flowers of any cultivar in the trial. Its upright, rigid stems create a strongly vertical aesthetic while the dull green leaves are highly mildew resistant and have a rough, sand-papery texture, not glossy as other beebalms.

Monarda ‘On Parade’ performs similar to the trio of purplish-red cultivars, ‘Judith’s Fancy Fuchsia’, ‘Colrain Red’, and ‘Rapsberry Wine’. All grow to about 4 feet tall with fair mildew resistance. ‘On Parade’ stands out for its brilliant, orchid purple flowers.

Monarda ‘Gardenview Scarlet’ (didyma type) is the only true red-flowering cultivar with consistent powdery mildew resistance. It has large, 4 inch wide flowers that attract lots of hummingbirds. Cultivar is similar to ‘Jacob Cline’, except it grows only 36 inches tall, almost 1 foot shorter.

Runner-up popular favorites:

‘Prairie Gypsy’

‘Jacob Cline’

‘Purple Mildew Resistant’

‘Cambridge Purple’

‘Peter’s Purple’

‘Pink Surprise’

*I encourage blog readers to read the entire Monarda Trial Report on the MT. Cuba Gardens website.