Sunday, 31 January 2016

Muscari azureum (Pseudomuscari azureum)

Pseudomuscari azureum (syn. Muscari azureum), the azure grape hyacinth, is a species of flowering bulbous perennial, native to Turkey. It is grown in gardens for its spring flowers. Azureum means "bright blue", a reference to its flower colour.












Description
Pseudomuscari azureum is a small plant, around 4–15 cm (1.6–5.9 in) high with two to three grey-green leaves per bulb. Up to 60 flowers are borne in Spring (March or April in the Northern Hemisphere) in a dense "spike" (raceme). Each flower is 4–5 mm (0.16–0.20 in) long and bright blue in colour with a darker stripe along each of the lobes. A feature which distinguishes the genus Pseudomuscari from the related Muscari is that the mouth of the flower is not narrowed but forms an open bell-shape. It grows in alpine meadows in north and east Turkey.



Cultivation
P. azureum may be found in horticultural sources under the illegitimate name Hyacinthus azureus. It is still widely referenced under its previous name Muscari azureum. The species is popular as a spring-flowering bulb though rarely offered for sale in average garden centres. It can be used in rock gardens or underneath shrubs. It is frost-hardy and should be grown in full sun. It has gained the Royal Horticultural Society's Award of Garden Merit. There is a white cultivar, 'Album'

Thursday, 28 January 2016

Iris fulva - the copper iris

Iris fulva is a rhizomatous perennial, native to the southern and central United States. It has deep bright red flowers and bright green leaves.

It is not widely grown in the United Kingdom.

I first heard about it Dan Pearson's book 'Sanctuary in the city' in which he talks of obtaining iris fulva from Piet Oudolf, the famous Dutch plantsman.

Ever since then I have been on the hunt for it.

It is frost hardy in Cambridge UK. I grow it both in large pots and in a shallow marshy area, both receive a lot of sun. Apparently these need a bit of spring sun and warmth to flower well.

They have reliably flowered for me with the most beautiful colours.


It normally flowers between spring and early summer, between April and June, with 1 or 2 flowers per axil of each alternate leaf along the stem. There can be as many as 4-6 (occasionally more) flowers per stem. The blooming period lasts for about 3 weeks.

Dendrobium Stardust Firebird

Dendrobium Stardust Firebird is a complex hybrid crossing between Dendrobium unicum, monoliforme, heterocarpum (syn. aureum) and signatum.

I grow it in intermediate conditions, with 12-14 degrees C at night in winter, in an east facing window that gets sun both in summer and in winter. I grow it in a very fast draining mixture, and let the growing medium dry out thoroughly before watering again.

Some suggest it needs a nobile type dry winter rest, but I have found that seems to weaken the plant, which looses its leaves and then subsequent canes are smaller. Instead I water it weekly throughout the year.




Flowers form on last years canes, and on any nodes on previous years' canes that haven't yet flowered. It flowers in the spring (northern hemisphere, London UK) for me, around April - May, with flowers that are a beautiful orange. The Stardust Chyomi hybrid flowers a month or so before. The flowers last for a good 4 to 6 weeks and are beautiful.

Saturday, 23 January 2016

Dendrobium delicatum culture

Dendrobium Delicatum is a naturally occurring hybrid between Dendrobium kingianum and Dendrobium speciosum var hilli



It occurs along the Great Dividing Range in south east Queensland, as a lithophyte.

D. x delicatum is primarily a lithophyte (growing on rocks). It is variable in habit, which is to be expected as its parents are also variable in habit. 

The pseudobulbs can be up 20 to 35 cm long, thickest near the base and tapering towards the apex. There are usually 2 to 5 thick leaves at the top of each pseudobulb, the leaves being 75 to 175 mm long. The bulbs and leaves are very thick and are resistant to pest. The plant has a lovely profile and looks great in a terra cotta pot. 

Flowers occur on 250 mm long stems in clusters of up to 14 or more flowers. They are usually pure white to cream with purple dots on the labellum and are usually long lasting and sweetly scented. Flowers are seen from late winter to spring.

Any free draining compost will do for this plant, which is not really fussy. It is a fast grower and prolific bloomer. 
Temperature.
D x delicatum is very well suited to outdoor cultivation in temperate regions, with frost protection in a greenhouse or conservatory during the winter. It should not be grown in dense shade or flowering will be discouraged. 

Watering can be done freely during spring, summer and autumn and  should be kept to a minimum during winter.

Tuesday, 19 January 2016

Graptopetalum paraguayense - Mother of Pearl Plant - Ghost plant

Origin and Habitat: Graptopetalum paraguayense, originally thought to be native to Paraguay, as the species name implies, was first ‘discovered’ in a load of cactus plants imported to New York in 1904. No plants of the species have been rediscovered in the wild since. The ssp. bernalense was found in 1979 by Alfred Lau on the Cerro Bernal mountain range of Tamaulipas state in NE Mexico, and it is thought that this may be near the home of G. paraguayense also. Another possible variation, ssp. mendozae, was found much more recently.


Description: Graptopetalum paraguayense is a clump-forming, perennial succulent with a basal rosette of thick fleshy leaves resembling Echeveria. The common names include Mother-of-pearl-plant and Ghost plant probably with reference to the look of the greyish white, opalescent leaves. This is not to be confused with Monotropa uniflora which is also referred to as the “Ghost Plant”. Plants turn pinkish yellow in hot, dry conditions and blue-gray when pampered with partial shade and regular water. They bear star-shaped, white-and-red flowers in spring. Graptopetalums may form crested growth.

Habit: Graptopetalum paraguayense is a hairless, perennial rosette-forming, succulent plant, looking like an Echeveria but unlike Echeveria the rosettes grow at the tips of ever-lengthening stems creating a low spreading colony to only about 30 cm tall. 

Rosettes: 9-15 cm across, with c. 15-25, loosely shingled, leaves, and forming a symmetric Fibonacci spiral. Old leaves at the base of the rosette wither and fall off. New growth is from the centre of the rosette, so over time the stem gets denuded, with a rosette on the end.

Leaves: 2-8 cm long 1.5-2.5 cm broad, thick triangular to spathulate, pointed, flat or hollowed above, keeled beneath. The leaves range in colour (even on the same plant) from grey-green, pale blue, light pinky-lilac, to light purple and are covered by a greyish bloom giving the whole plants an opalescent shine (Exhibiting a milky iridescence like that of an opal or pearl). The thick leaves hold excess moisture so the plant can withstand periods without rain.

Flowers: Star shaped, white with small red specks, c.2 cm in diameter, borne on stems to 15 cm long with 2-6 branches, each with 3-14 flowers. Petals c. 1 cm long white, dotted with red. 

Blooming season: The plant flowers occasionally in late winter-early spring.


Cultivation and Propagation: Culture of Graptopetalum paraguayense is fairly easy, it can tolerate full sun (where it will stay compact) but a much better exposure is light shade. It is always a favorite carefree windowsill citizen, an excellent addition to any garden. The plant's origin will make its rosettes tolerate heat and drought. They are true survivors.

Exposition: Likes light shade to part sun (it will take a few hours of sun without a problem), but adapts very well to full sun and shade too. It can overwinters well also under grow lights in a cool room of the house. Graptopetalums are chameleons. Those grown in partial shade tend to be blue-gray; in full, hot sun, gray-pink; in full sun, pinkish gray to yellow.

Soil: Although it needs a soil that is gritty and porous with good drainage, the soil must be able to hold the moisture that the plant requires. The ideal soil should contain equal parts of loam with small gravel added (eg pumice or lava grit). Good drainage is essential.

Watering: During the summer growing period the plant appears to need much more water than the average succulent. Water when plant is dry and do not water again until the soil is completely dry again. Dislikes over-watering. Pay particular attention to make sure that they do not rot at the root from soggy soil. During October to March, water very sparingly, using only enough water to keep the foliage from shriveling. In a very humid situation in winter, it can rot even if totally dry. It likes dry air as much as dry soil. 

Hardiness: It is usually recommended to avoid freezing temperatures, but this is a very hardy succulent and can rebound from being frozen and is useful in areas that drop below 7° C. It requires low temperature for flower formation and it will not flower unless it is overwintered for at least a month at 15° C or less.

Pests and diseases: The tightly-packed rosettes can sometimes harbour mealy bugs, but generally it is pest free and easy to grow.

Uses: A great plant for use as a groundcover, in gravel gardens, paved areas, rockeries, in hanging baskets or pots, or for spilling over walls. Like all succulents it is not for planting in areas with much foot traffic. It is best to pick a good location for the ghost plant and then don’t move it. It mixes beautifully with other succulents and alpines.


Propagation: It is is propagated by the division of offshoots or by individual leaves, rooted in sand or in dry vermiculite. Any rosette that breaks off has the potential to root and start a new plant. Even a leaf that drops off will root below the parent plant and produce a new rosette quickly. Because leaves and cuttings root effortlessly, graptopetalums are among the easiest succulents to propagate.

Tuesday, 12 January 2016

Dendrobium Speciosum - the Rock Lily - Tar-Beri

Dendrobium speciosum is native to a vast section of Australia ranging from Mallacoota (37°33'S) south-east Victoria to the tropical conditions up past Cairns (16°57′S).

It is known as "Tar-Beri" to the aborigines, and "Rock Lily" or "King Orchid" to other Australians. It blooms extraordinarily flower-laden plumes, like bushy fox tails, of fragrant, creamy white flowers. The showy flowers grow in long racemes on straight or slowly arching, long, starchy stems with over 100 small sweetly fragrant flowers per stem from August to October in Australia, or February to April in the Northern hemisphere. Their color varies from white to creamy yellow. The white labellum is covered with purple dots and veined with red and purple.




There are two to five thick, leathery leaves originating from the top of each pseudobulb. These leaves can remain on the plant for up to 12 years. The erect or curved pseudobulbs are rather large, up to 45 cm long. They are thickest at their base (5 to 7 cm), and often taper towards the apex (3 cm).


Cultivation

This is an orchid that thrives on low-medium humidity, bright to very bright light and an open well drained pot with orchid compost.

A constantly moist root system is important, as in natural cliff faces they live on weep moisture constantly. Water all year round in moderation.I n the wild, it is nearly always growing on granite cliff faces or boulders in open grassy paddocks. The speciosum's root systems are often covered with a blanket of moist ferns and mosses.




These orchids are great growers and in time can get huge!

Very bright, open, breezy positions in the growing season seem to be the key to mass blooming.

Speciosums can be acclimatised to take 100% full-sun if slowly positioned into brighter and brighter light from late winter onwards. It is in these full sun positions that they will bloom annually without fail.

It is extraordinarily tough, hardy and drought tolerant. It can tolerate short periods of temperatures near frost to over 45°c without severe damage.

So, growing dendrobium speciosum is simple. Avoid frosts, unaccustomed hot sun, too much shade (make sure you can see a shadow when placing hand above foliage) and temperatures above 36c if possible. Anywhere that has similar conditions to south-eastern Australia will be able to grow this orchid with ease. In the UK the orchid will thrive in full sun outside during summer with overwintering in a cool greenhouse.

Pots should always have excellent drainage and not be too large in comparison to the orchid. As they are vigorous growers, re pot annually.  The compost should be open well drained and have about 25% rock present.

They are virtually free of pests, as their foliage is beautifully thick and sturdy. 

Some subgroups.

Because dendrobium speciosum is found over such a vast region, botanists have broken the species apart into many subspecies or varieties. The naming of these groups is subject to regular review and change!

The far Southern form known as dendrobium speciosum var speciosum is the easiest to grow (and most tolerant of low temperature). 

The deepest colour forms are unusual variants of speciosum var grandiflorum, these may be rich golden yellow, and sometimes in full sun almost a golden orange.

Generally a good rich daffodil yellow is to be expected. In nature most clones are a pale lemon or yellow/cream in colour, very rarely are true clear whites seen.

The shortest caned forms are the pedunculatum forms from furthest north Queensland. They may have fully mature blooming sized canes at only 3" tall!


The Hillii variety tends to produces clawed tiny blooms in pale creams on disproportionately giant canes, which is great in nature but not usually preferred by growers.

Saturday, 2 January 2016

Bowiea volubilis - climbing onion - unusual succulent

Bowiea volubilis subsp volubilis has an unusual succulent adaptation - climbing inflorescences that harvest photosynthetic light in the absence of aerial leaves. 



It is a deciduous climber which climbs to 3-4 m in surrounding vegetation or scrambles over rocks on hillsides. The bulb is large, reaching 150 mm in diameter, with several fleshy white scales becoming greenish-yellow if exposed. Stems are fleshy, bright green, much branched and function as leaves. 




Flowers are 16-24 mm in diameter, green, with stalks turning backwards. Fruits are in the 
form of an oval capsule, about 25 mm in diameter.




B. volubilis capsule


Distribution and habitatBowiea volubilis subsp volubilis  has a wide distribution and occurs in the eastern parts of South Africa ranging from the Eastern Cape to Limpopo Province. It extends north into Zimbabwe, Zambia, Tanzania, Uganda and Kenya and has also been recorded in Mozambique, Malawi and Angola. It grows generally at low and medium altitudes in a variety of habitats.


Bowiea volubilis flowers




Bowiea was named by W.H. Harvey to honor James Bowie (1789-1869), a plant collector for Royal Botanical Gardens, Kew. The genus is monotypic with two subspecies – volubilis and gariepensis - both occurring in South Africa. The epithet volubilis is a reference to the subspecies' twining growth whereas gariepensis is a reference to the geographical area of growth. The subspecies grow in separate geographical areas and show differences in floral, capsule and seed characters.


Bowiea volubilis subsp volubilistolerates wet and dry conditions, growing predominantly in summer rainfall areas, which receive approximately 200 - 800 mm of annual rainfall. It flowers between January and March.


Bowiea is used extensively for medicinal purposes for various skin diseases, sore eyes, bladder problems, barrenness, to facilitate delivery, and to procure abortions. Its magical properties are well-regarded. Warriors are made brave and invincible, travellers protected, and love procured with this strange-looking plant.
As a result, in southern Africa this species faces severe threat due to the medicinal market.


Growing Bowiea volubilis
Few seeds are set, making offspring numbers low. If fruit are produced, the fine black seeds should be harvested as soon as the capsules start to split. The seeds should be sowed immediately onto a mix of one third sand and two thirds bark in seedling trays, and left for germination in semi-shade.
Vegetative propagation of Bowiea volubilis subsp volubilis is extremely slow and requires expensive tissue culture systems.