Plant List 2009 - O

Oenothera		"Crown Imperial"	A clump forming perennial with rich green leaves and heads of bright yellow flowers arising from red buds. Height 40-50cm. Moist well-drained soil in sun. Jun.-Aug.
Oenothera		"Crown of Gold"	A clump forming perennial whose foliage in winter is dark green edged orange-yellow, becoming lighter and brighter in spring and summer. Heads of bright yellow flowers arise from red buds. Height 40-50cm. Moist well-drained soil in sun. Jun.-Aug.
Oenothera		"Summer Sun"	A perennial "Evening Primrose" with red flushed leaves and clusters of red budded bright yellow flowers. Height 45cm. Well-drained soil in sun.
Oenothera		ex "Colin Porter"	Lax stems of bright green leaves with terminal clusters of red flowers with a yellow edge. Height 15cm. Well-drained soil in sun. Jun.-Aug.
Olearia	macrodonta	"Minor"	An upright evergreen shrub with holly-like glossy, dark grey-green leaves and dense clusters of fragrant, daisy-like, white flowers with a reddish brown eye. Height 3m. Spread 2.5m. Well-drained soil in sun. Flowers from June to August.
Olearia	nummulariifolia		An evergreen rounded bush with leathery dark green whorls of tiny leaves and clusters of daisy-like, fragrant, white flowers in mid-summer. Height 2m. Spread 2m. Well-drained soil in full sun. July to August.
Olearia	phlogopappa	"Combers Pink"	An evergreen upright bush with grey-green leaves, white-woolly beneath and clusters of daisy-like, pink flowers with a yellow centre. Height 2m. Well-drained sheltered site in sun. Jul.-Aug.
Olearia	x haastii		A dense, bushy, evergreen shrub with glossy, dark green leaves and dense clusters of daisy-like, white flowers with a yellow eye. Height 2m. Spread 2m. Well-drained soil in sun. Flowers from July to August.
Olearia	x macrodonta		An upright, evergreen shrub with holly-like glossy, dark green leaves and dense clusters of fragrant, daisy-like, white flowers with a reddish brown eye. Height 6m. Spread 5m. Well-drained soil in sun. Flowers from June to August.
Olearia	x mollis		A compact rounded shrub with wavy-edged, silvery-grey slightly toothed leaves.Large corymbs of creamy white daisy flowers. Height 1m. Well-drained soil in sun. May.
Olsynium	douglasii		Grass-like stems carry nodding bells of purple,pink or white flowers in early Spring. Dies down by June. Height 15cm. Moist soil in part shade.
Olsynium	douglasii	"Alba"	Grass-like stems carry nodding bells of white flowers in early Spring. Dies down by June. Height 15cm. Moist soil in part shade.
Omphalodes	cappadocica	"Cherry Ingram"	An evergreen perennial with lustrous leaves and pretty deep blue flowers. Height 20-25cm. Best in moist soil in part shade. March to April.
Omphalodes	cappadocica	"Starry Eyes"	An evergreen perennial with lush green ovate foliage and deep blue flowers and a central white stripe on each petal. Mar.-Apr. Height 25cm. Moist, fertile soil in part shade or dryer in full shade.
Omphalodes	verna		A semi-evergreen perennial with creeping stems and pretty bright blue flowers with a white eye in spring. Height 20cm. Moist soil in part shade. Mar.-May.
Omphalodes	verna	"Alba"	A semi-evergreen perennial with creeping stems and white flowers. Height 20cm. Moist soil in part shade. Mar.-May.
Onoclea	sensibilis		Sensitive Fern. A deciduous fern with bold green triangular fronds, which emerge a pinky bronze colour. Height 60cm. Moist soil in part shade. good pond-side plant.
Onosma	albo-rosea		Basal rosettes of grey-green leaves, with inflorescences of showy white flowers fading to pink. Height 15-25cm. Well-drained soil in sun. Mar.-Apr.
Onosma	rigida		Neat mounds of narrow grey-green leaves and bearing nodding clusters of very lovely, tubular, light yellow flowers, each an inch or more long. Height 30cm. Well-drained soil in sun. May-Jun.
Ophiopogon	jaburan		An evergreen spreading perennial with arching grass-like leaves and small white to pale purple flower spikes followed by violet fruits. Height 40cm. Moist well-drained soil in part shade. Jun.-Aug.
Ophiopogon	japonicus	"Nippon"	Small tufts of arching green grass-like leaves bearing stalks of pink flowers followed by translucent blue-mauve berries. Height 10cm. Moist soil in part shade.
Ophiopogon	japonicus	"Tama-ryu"	Small tufts of arching deep green grass-like leaves bearing stalks of pink flowers followed by translucent blue-mauve berries. Height 5-10cm. Moist soil in part shade.
Ophiopogon	japonicus	"Variegatus"	Evergreen, clump-forming perennial with green, white edged leaves and lilac flowers in late summer. Height 25cm. Full sun in well-drained soil.
Ophiopogon	planiscapus	"Little Tabby"	A clump-forming evergreen perennial with narrow, curving, green, silver variegated leaves and clusters of white flowers . Height 15cm. Moist well-drained soil in part shade. Jul.-Aug.
Ophiopogon	planiscapus	"Nigrescens"	A clump-forming evergreen perennial with narrow, curving, almost black leaves. Clusters of pale purple flowers followed by almost-black fruit. Height 20cm. Moist well-drained soil in sun or shade. Jul.-Aug.
Origanum		"Barbara Tingey"	A dense evergreen subshrub with bluish green leaves and clusters of tubular pink flowers. Height 10cm. Well-drained soil in sun. Jun.-Sep. Probably best with winter protection.
Origanum		"Buckland"	Arching stems of small grey-green leaves. Pinky mauve flowers within showy bracts. Height 15cm. well-drained soil in sun. Jun.-Aug.
Origanum		"Dingle Fairy"	Upright stems of bright green leaves topped by mauve flowers. Height 20cm. Well-drained soil in sun. Jun.-Aug.
Origanum		"Frank Tingey"	Upright stems with clusters of tubular pink flowers with pretty deep pink bracts. Height 20cm. Well-drained soil in sun. Jun.-Aug.
Origanum		"Kent Beauty"	An evergreen subshrub with and clusters of tubular pink to mauve flowers with deep rose-pink bracts in summer. Height 10cm. Jun.-Aug.
Origanum		"Rotkugel"	An erect perennial with dark green leaves and clusters of large red mauve flowerheads. Height 50cm. Well-drained soil in sun. Jul.-Sep.
Origanum	amanum		An evergreen subshrub with bright green leaves and clusters of long tubular pink flowers with pretty, green bracts flushed pink with age. Height 10-15cm. Well-drained soil in sun. Jun.-Sep.
Origanum	calcaratum		An upright subshrub with grey leaves and erect spikes of pink flowers in summer. Height 30cm. Well-drained soil in sun. Jun.-Aug.
Origanum	dictamnus		An evergreen subshrub with clusters of funnel-shaped pink flowers with purple bracts. Height 15cm. Sunny, well-drained spot. Protect from winter wet.
Origanum	laevigatum		An erect perennial with dark green leaves and clusters of small funnel-shaped purplish pink flowers with purple-red bracts. Height 45cm. Well-drained soil in sun. May-Sep.
Origanum	minutaeflorum		Tiny grey aromatic leaves with terminal clusters of purple-pink flowers. Height 15-20cm. Well-drained soil in sun. Aug.-Sep
Origanum	rotundifolium		A perennial with blue-grey leaves and small tubular pink flowers with pretty pale lemon green bracts in summer. Height 10-35cm. Jun.-Aug.
Origanum	vulgare	"Thumble's Variety"	A mound of golden green leaves and clusters of small tubular white flowers. Height 25cm. Sun in well-drained soil. Jul.-Sep.
Orixa	japonica	"Variegata"	A deciduous shrub with puckered leaves, shaded silvery-grey with a broad creamy white margin. Small greenish, pungently scented flowers are borne in panicles on old wood as the leaves emerge. Height and spread 2.5m. well-drained soil in sun or part shade.
Orthrosanthus	laxus		A clump forming perennial with strap-like leaves and spikes of flat six-petalled flowers. Height 30-40cm. Well-drained soil in sun. Jun.-Jul. Needs winter protection.
Osmanthus	decorus		A dense evergreen shrub with glossy, dark green leaves and clusters of tubular white flowers. Height 3m. Spread 5m. Well-drained soil in sun or part shade. Flowers from April to May.
Osmanthus	delavayi		A dense evergreen shrub with glossy, dark green leaves and clusters of tubular white flowers in mid-spring. Height 3m. Spread 5m. Well-drained soil in sun or part shade. April to May.
Osmanthus	heterophyllus	"All Gold"	A dense, upright, evergreen shrub with holly-like, glossy, leaves dull yellow when young and clusters of fragrant tubular white flowers. Height 1.5m. Spread 1m. Well-drained soil in sun or part shade. Flowers from August to September.
Osmanthus	heterophyllus	"Goshiki"	A dense rounded shrub with holly-like, glossy, dark green, white and pink leaves, bronze when new, and clusters of fragrant tubular white flowers. Height 2m. Spread 2m. Well-drained soil in sun or part shade. Flowers from September to November.
Osmanthus	heterophyllus	"Purpureus"	A dense, upright, evergreen shrub with holly-like, glossy, leaves metallic purple when young and clusters of fragrant tubular white flowers. Height 2.5m. Spread 2m. Well-drained soil in sun or part shade. Flowers from August to September.
Osmanthus	heterophyllus	"Variegatus"	A dense, rounded, evergreen shrub with holly-like, glossy, dark green leaves variegated creamy white and clusters of fragrant tubular white flowers. Height 1.8m. Spread 1.8m. Well-drained soil in sun or part shade. August to September.
Osmanthus	x burkwoodii		A rounded evergreen shrub with glossy, dark green leaves and clusters of very fragrant tubular white flowers. Height 3m. Sun or part shade. Apr.-May.
Osmanthus	x fortunei		An evergreen shrub of dense habit with large, broad, dark glossy green holly-like leaves and small white fragrant flowers. Height and spread 3m. Moist well-drained soil in sun or part shade. Flowers from August to September.
Osmunda	cinnamomea		Related to the "Royal Fern", the emerging fronds are covered in white woolly hairs. Height 80cm. Moist soil in part shade.
Osmunda	regalis		"Royal Fern". A deciduous fern forming dense clumps of dainty, thin, fleshy fronds that unfurl coppery-brown before turning green. Height 1.5m. Wet acid soils in dappled shade.
Osmunda	regalis	"Cristata"	A flat crested form of the "Royal Fern". Deciduous with thin fleshy fronds opening coppery brown. cresting becomes more prominent in older specimens. Height 1-1.2m. Moist soil in part shade.
Osmunda	regalis	"Purpurescens"	"Purple Royal Fern". Larger growing than the type species with the young fronds unfurling a purplish colour and the stems staying purple throughout the season. Wet acid soils in dappled shade.
Osteospermum		"Lady Leitrim"	Hardy evergreen perennial with pale pink flowers from Apr-Sep. Height 30cm. well-drained soil in sun or part shade.
Osteospermum	jucundum var. compactum		A compact neat, evergreen, clump-forming perennial with greyish green leaves and mauve-pink flowers with purple on the reverse and a purple eye. Height 20cm. Spread 60cm. Well-drained soil in sun. May-Sept.
Ostrya	carpinifolia		A large rounded deciduous tree with toothed dark green leaves with pendulous yellow catkins in spring and pretty hop-like white fruit clusters in summer. Height 20m. Spread 20m. Well-drained soil in sun or part shade.
Ourisia	macrophylla		A mat-forming, evergreen, perennial with bright green leaves and dense clusters of white flowers. Height 30cm. Moist soil in part shade. Jun.-Aug.
Oxalis		"Ione Hecker"	A clump-forming perennial with clover-like grey-green leaves and pretty funnel-shaped, violet-blue flowers conspicuously veined dark purple. Height 8cm. Moist well-drained soil in sun. May-Jul.
Oxalis	adenophylla		A clump-forming perennial with clover-like, grey-green leaves and funnel-shaped, pink flowers with a white centre. Height 10cm. Moist well-drained soil in sun. Apr.-May.
Oxalis	depressa		A clump-forming perennial with clover-like, grey-green leaves, and pretty funnel-shaped, deep rose-pink flowers. Height 5cm. Well-drained soil in sun or part shade. Jun.-Aug.
Oxalis	enneaphylla		A clump-forming perennial with clover-like blue-grey leaves and pretty funnel-shaped, light pink, fragrant flowers with purple veining. Height 8cm. Moist soil in sun or part shade. May-June.
Oxalis	enneaphylla	"Sheffield Swan"	A clump-forming alpine with finely dissected blue-grey leaves and large funnel-shaped, white flowers. Height 8cm. Sunny spot on scree or Alpine House in well-drained soil. May-Jun.
Oxalis	imbricata		Deep rose-pink flowers over clover-like foliage. Height 8cm. Well-drained soil in sun. Oct.-Nov. Dormant throughout summer.
Oxalis	lobata		Clump-forming with clover-like green leaves which appear in early spring, die down and reappear in autumn. Pretty funnel-shaped, bright yellow flowers. Height 10cm. Well-drained soil in sun. Aug.-Oct.
Oxalis	purpurea	"Ken Aslet"	White hairy, dark green leaves and pretty, widely funnel-shaped bright yellow flowers. Height 10cm. Moist well-drained soil in sun. Sep.-Dec.
Oxalis	squamata		Deep pink flowers with a yellow eye over small grey-green clover-like leaves. Height 10cm. Gritty soil in full sun. Jun.-Oct.
Oxalis	stipularis		Bulbous perennial with hanging flowers of pink with a white eye. height 15cm. Gritty soil in sun. Needs winter protection. May-Jul.
Oxalis	triangularis ssp. papillionacceae		Triangular shaped leaflets, green with a purple back and stems of pure white flowers. Height 25cm. Well-drained soil in sun. or part shade. Aug.-Oct. Needs Winter protection.
Oxydendron	arboreum		A narrow deciduous tree or shrub with glossy, dark green leaves, turning brilliant shades of red, yellow and purple in autumn. Large clusters of white flowers. Eventual height 10-15m. Spread 8m.Moist well-drained acidic soil in sun or part shade. Flowers
Ozothamnus	ledifolius		A compact, evergreen, rounded bush with yellowish green stems covered with narrow, dark green leaves and carrying clusters of white flowers. Height 1m. Spread 1m. Well-drained soil in sun..Flowers from June to July.
Ozothamnus	selago		A clump-forming evergreen alpine with thread-like jade-green and silver leaves. Sometimes produces small white flowers. Height and spread 10-15cm. Well-drained soil in sun. Jun.-Jul. May need winter protection.