September Archives

Perovskia ‘Little Spire’

Culture: Easily grown in average, dry to medium, well-drained soils in full sun. Sharp soil drainage is especially important. Avoid wet, poorly drained soils. Plants have good drought tolerance. Best flowering occurs in full sun locations. Stems are more likely to flop if plants are grown in part shade. Cut back plants almost to the ground in late winter to early spring as soon as new growth appears.

Although the taller species sometimes benefits from a spring pinching to control height, this small cultivar performs well without pinching.

Noteworthy Characteristics: Perovskia atriplicifolia, commonly called Russian sage, is a woody-based perennial of the mint family which typically grows 2-4′ (less frequently to 5′) tall and features finely-dissected, aromatic (when crushed), gray-green leaves on stiff, upright, square stems and whorls of two-lipped, tubular, light blue flowers tiered in branched, terminal panicles (12-15″ high). Long summer bloom period. Perennial Plant Association Plant of the Year (1995).

Genus name honors Russian general V. A. Perovski (1794 – c. 1857).

Specific epithet means with leaves resembling salt-bush.

‘Little Spire’ is a compact Russian sage cultivar which typically grows to 2′ tall (species typically grows to 3-4′). It is a woody-based perennial of the mint family. Features finely-dissected, aromatic, gray-green foliage on stiff, upright, square stems. Whorls of 2-lipped, tubular, violet-blue flowers tiered in branched, terminal panicles appear over a long summer bloom. Silvery foliage can provide good winter interest in warm winter climates.

Problems: No serious insect or disease problems. Plants tend to sprawl or flop over as the summer progresses.

Garden Uses: Mass or specimen in borders. Provides long summer bloom for the perennial border. Contrasts well with both pink (e.g., phlox, mallow or roses) and yellow (e.g., rudbeckia) perennials.

Edger along paths. Gray-green foliage and blue flowers provide good texture, color and contrast to many other summer blooming plants.

Phlox ‘David’

Culture: Grow in moderately fertile, medium moisture, well-drained soil in full sun to part shade. Best in full sun. Prefers rich, moist, organic soils. Also prefers moderate summer temperatures over the heat and humidity of the deep South. Needs good air circulation (space well and thin out stems as needed) to help combat potential powdery mildew problems. Intolerant of drought and needs to be watered in dry spells. Avoid overhead watering however. Appreciates a summer mulch which helps keep the root zone cool. For winter, cut plants to the ground and remove from the garden plus clean up all plant areas in order to minimize possible powdery mildew infection for the following growing season. Remove faded flower panicles to prolong bloom period and to prevent unwanted self-seeding (cultivars generally do not come true from seed).

Noteworthy Characteristics: Phlox paniculata, commonly known as garden phlox, is native from New York to Iowa south to Georgia, Mississippi and Arkansas. It has escaped gardens and naturalized into areas beyond its original native range. In Missouri, it is typically found south of the Missouri River in moist or rich low woods, thickets, alluvial banks and gravel bars along streams and bluff bases (Steyermark). This is an upright perennial that grows in a clump to 2-4′ tall and to 2-3′ wide on stiff stems clad with conspicuously veined, opposite, pointed, elliptic, deep green leaves (to 4-6″ long). Fragrant, tubular, pink-purple to white florets (to 3/4” diameter) are densely packed in large, tiered, domed terminal clusters (to 6-8″) over a long July to September bloom period. Each individual floret has a long corolla tube and five flat petal-like lobes. Butterflies love the flowers.

A large number of garden phlox cultivars in flower colors including white, lavender, pink, rose, red and bi-color are available in commerce. Cultivars resistant to powdery mildew are often the best choices.

The genus name is derived from the Greek word phlox meaning flame in reference to the intense flower colors of some varieties.

Specific epithet refers to the plant bearing flowers in panicles.

‘David’ is a garden phlox cultivar that typically grows in an upright clump to 3-4′ tall. Fragrant, tubular flowers (1/2″ to 1″ diameter) with long corolla tubes and five flat petal-like lobes are pure white. Individual flowers are densely arranged in large, terminal, pyramidal clusters (panicles to 6-12″ long) in summer atop stiff, upright stems which seldom need staking. Long mid to late summer bloom sometimes extends into early fall. Narrow, opposite, pointed, lance-shaped leaves (to 5″ long). Good fresh cut flower.

Problems: Phlox is not always an easy plant to grow well. Phlox bugs, powdery mildew and root rot can be serious problems. Spider mites can also be a problem, particularly in hot, dry conditions. Taller stems may need staking.

By reputation, ‘David’ has good resistance to powdery mildew.

>Garden Uses: Garden phlox is a staple of the perennial border. Mixes well with other perennials and provides long summer bloom. Regardless of flower color, garden phlox is attractive to hummingbirds and is a good selection for inclusion in a bird garden.

Campanula C. ‘White Clips’

Campanula carpatica, the tussock bellflower or Carpathian harebell, is a species of flowering plant in the family Campanulaceae, native to the Carpathian Mountains of Central Europe. It is a low-growing herbaceous perennial, with long stems bearing solitary blue bell-shaped flowers. It was introduced to the Royal Botanic Garden at Kew in 1774 by Nikolaus Joseph von Jacquin. Several cultivars in shades of white, blue, pink and purple, have been developed for garden use.

Phlox ‘Laura’

Laura garden phlox blooms in mid-summer with round heads of large, lavender-purple flowers that are delightfully fragrant. The foliage is mildew resistant and this perennial grows easily in compost enriched garden soil.

24-30″ tall x 18″ wide (cutting propagated). If you love flowers with rich, saturated colors (and who doesn’t!), Phlox ‘Laura’ is a “must have” cultivar for your perennial flower beds. The white-eyed deep lavender-purple flowers are are deliciously fragrant. The plant’s foliage has excellent mildew resistance making it a wonderful, low maintenance garden phlox. Plant ‘Laura’ in compost enriched garden loam and irrigate regularly.

Rudbeckia ‘Goldsturm’

It is an herbaceous perennial growing up to 120 cm (47 in) tall, with bright yellow daisy-like composite flower heads.

Growth and reproduction: In the garden, this plant spreads aggressively by both stoloniferous stems and seed. The seeds are produced in fruits called cypselae, which are 2.2 to 4 mm long and have short coroniform pappi, 0.2 mm long. The ripe seed is a favorite food of finches in winter.

Morphology: Stems are hairy, ridged, and dark green. Leaves are dark green, sparsely but roughly haired, simple, with sparsely serrate margins. Flowers are heads, with black disk florets and bright orange ray florets, borne singly on stems that extend above the foliage. Stems are glabrous or moderately covered in hirsute hairs with spreading branches. The leaves have blades that are lanceolate to broadly ovate or elliptic in shape without lobes. The leaf bases are attenuate to cordate in shape and the margins of the leaves are usually entire or serrate, or sometimes lacerate. The upper surfaces of the leaves are glabrous or have hirsute to strigose hairs. The basal leaves are petiolate, with petioles that are 5 to 30 cm long and 1 to 8 cm wide, the cauline or stem leaves have petioles that are 2 to 25 cm long and 0.5 to 7 cm wide, the bases are attenuate to cordate or auriculate in shape.

The flower heads are often produced one per stem but are also often produced in corymbiform arrays with 2 to 7 flowers per stem. The cups that hold the flowers called receptacles, are hemispheric to ovoid in shape with paleae 2.5 to 4 mm long, the apices are obtuse to acute in shape with the ends usually glabrous and the apical margins ciliate. The flower heads have 10 to 15 ray florets with laminae elliptic to oblanceolate in shape and 15–25 cm long and 3 to 6 mm wide. The abaxially surfaces of the laminae have strigose hairs. The flower discs or center cones are 12 to 16 mm tall and 10 to 18 mm wide, made up of 50 to over 500 disc florets, with the corollas proximally yellowish green and brown-purple distally in color, 3 to 4.2 mm long, having style branches 1.3 mm long.

Rudbeckia ‘Viette’s Little Suzy’

Culture: Easily grown in dry to medium, organically rich to average, well-drained soils in full sun. Best bloom occurs in full sun, although plants will tolerate some light shade. Plants prefer consistent moisture throughout the growing season, with some tolerance for drought once established. Good air circulation is appreciated. Deadhead spent flowers to encourage additional bloom. Plants slowly spread in the garden by rhizomes.

Noteworthy Characteristics: Rudbeckia fulgida is a Missouri native which occurs in both dry and moist soils in open woods, glades and thickets. An upright, rhizomatous, clump-forming, free-blooming coneflower which typically grows to 3′ tall, often forming colonies in the wild. Features daisy-like flowers (to 2.5″ across) with yellow rays and brownish-purple center disks. Prolific bloom production over a long mid-summer to fall bloom period. Oblong to lanceolate, medium green foliage. Good cut flower.

Genus name honors Olof Rudbeck (1630-1702) Swedish botanist and founder of the Uppsala Botanic Garden in Sweden where Carl Linnaeus was professor of botany.

Specific epithet means shining or glistening.

VIETTE’S LITTLE SUZY is a compact, upright, rhizomatous, clump-forming, free-blooming coneflower which typically grows only 10-15″ tall. Features daisy-like flowers with yellow rays and dark brownish-purple center disks. Prolific flower production over a long mid-summer-to-fall bloom period. Oblong to lanceolate, medium green foliage. Good fresh cut flower.

Problems: No serious insect or disease problems.

Garden Uses: Mass in bold drifts in the perennial border, cottage garden, meadow, native plant garden or naturalized area. Provides excellent bloom and color for the late summer. Good cut flower.

A compact cultivar.

Salvia ‘May Night’

Salvia nemorosa ‘May Night’. Garden sage. One of the most commonly used salvias in the northeastern US, it is covered in striking dark violet-blue flower spikes in May and June and remains upright and tidy throughout the season. Attracts birds, butterflies and bees. Makes an excellent cut flower, fresh or dried, and its leaves are freshly aromatic.

Sedum ‘Autumn Fire’

The border varieties of Stonecrop are a dependable choice for the late summer and fall garden, offering foliage interest earlier in the season, then a colourful display of flowers in the fall. This Canadian selection is an improvement on the older Autumn Joy, with a taller habit and stronger, less floppy stems. Plants begin to produce green broccoli-like buds in mid-summer, which gradually open into enormous dusty-rose flower heads, finally deepening to rich rusty-red during autumn. Even the dead flower heads have good winter effect. An outstanding cut flower, and also attractive to butterflies. Registered with COPF: royalty required for propagation.

Heuchera ‘Palace Purple’

This selection was the first of many purple-leaved Coral Bells, and is still an excellent choice for towards the edge of the border, or in containers and tubs. Plants form a low mound of maple-shaped leaves, from bronzy-green to rich purple-red. Spikes of small creamy-white flowers appear in early summer. In hot summer areas a part shade location will help to prevent the leaf colour from fading. Evergreen in mild winter areas, but plants may be clipped hard in early spring. Division is not always easy, but can be attempted in spring. A former Perennial Plant of the Year for 1991

Leucanthemum ‘Becky’

Easily grown in average, dry to medium, well-drained soils in full sun. Good soil drainage is essential. Wet soils in winter can be fatal. Tolerates some light shade, particularly in hot summer climates or when plants are being grown in dryish soils. Remove spent flower heads to promote additional bloom. Divide clumps as needed (every 2-3 years) to maintain vigor. Plants are somewhat short-lived. Consider cutting stems back to basal leaves after flowering to preserve plant energies and perhaps prolong plant life.

Noteworthy Characteristics: Leucanthemum x superbum, commonly called Shasta daisy, is a hybrid developed by Luther Burbank (1849-1926) in the 1890s near snow covered Mt. Shasta in northern California. Burbank crossed Leucanthemum vulgare (European oxeye daisy), Leucanthemum maximum (Pyrenees chrysanthemum), Leucanthemum lacustre (Portuguese field daisy) and Nipponanthemum nipponicum (Japanese field daisy) to produce Leucanthemum x superbum which was given the common name of Shasta daisy. This hybrid typically grows to 2-3′ tall with a spread to 18″ wide.

Leucanthemums were formerly included in the genus Chrysanthemum.

Genus name comes from the Greek leukos meaning white and anthemum meaning flower in reference to the white flowers of some species.

Specific epithet means superb.

‘Becky’ is larger than most other Shasta cultivars, growing 3-4′ tall on rigid stems which do not require staking. Features 3-4″ diameter flower heads with the classic white rays and yellow center disks and coarsely-toothed, lance-shaped, medium green leaves. Stems do not require staking. Long bloom period of July through September. Excellent and long-lasting fresh cut flower.

Problems: No serious insect or disease problems. Leucanthemums generally have some susceptibility to verticillium wilt, leaf spots and stem rots. Aphids, leaf miners and mites are occasional visitors.

Garden Uses: Shasta daisies provide long-lasting summer bloom and are mainstays of the perennial border, cottage garden and cutting garden. Rock gardens. Containers.

Bloom Time: September