This blog reviews the latest products, plants and innovations in gardening. It also provides a link for my many gardening friends who are members of the GardenMessenger and Seedmessenger Yahoo groups and their sub-groups that I moderate.

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I am a semi-retired UK botanical garden curator and former international horticultural consultant, who has worked extensively in Europe, the Middle East, North America and Australia. I spend part of the year in Australia and part in Europe, mainly due to family and work commitments. I earn my living from writing and editing Internet copy, articles and books. I have written over fifty books on gardening and have been translated into twenty-four different languages. I am a former UK Garden Writer of the Year and a previous Quill & Trowel Award Winner from the Garden Writer’s Association of America. I am interested in developing gardening communities on the Internet and I manage the popular GardenMessenger Yahoo group, along with its various sub-groups like PondMessenger and SeedMessenger. I also edit International Water Gardener and its associated regional web-sites.

Friday, June 02, 2006

Colorado Plants, Globe Artichokes and Biological Pest Control

Lonicera reticulata ‘Kintzley's Ghost’

The Plant Select choices for 2006 have been recently announced by Colorado State University and Denver Botanic Gardens in the United States This collaborative program between these two great institutions discovers and distributes the best plants for gardeners to grow in the high plains and intermountain regions. Several plants are chosen each year that thrive in the sunny variable conditions of Rocky Mountain gardens. These can be plants that have grown there for years and have not yet attained the popularity they deserve, or superior forms or hybrids carefully tested over time. While regionally focused, the program also provides very useful information and guidance for other gardeners with similar growing conditions in different parts of the world, and offers glimpses of plants that many of us would not otherwise know.

In reviewing the Plant Select choices, the one that caught my attention first was Kintzley's Ghost Honeysuckle. This is a selection from the Grape Honeysuckle, Lonicera reticulata, and was originally brought to Colorado by the family of an early horticulturist, William Kintzley. The honeysuckle was found on his grave in the 1960s. It is easy to grow, covering from 2.4-3.6m (8-12 ft) in height and having a spread of 90cm-1.5m ( 3-5 ft) in width. It apparently is quite content growing in an average garden loam soil and benefits from moderate irrigation. The plant produces yellow flowers surrounded by a silvery-white bract during early to mid summer. It is suitable for USDA zones 4 - 8.

Penstemon rostriflorus

Bridges' Penstemon, Penstemon rostriflorus, presumably named for that indefatigable Victorian botanist Thomas Bridges, is noted for flowering later in the season and for living longer than other commonly grown penstemons. The orange-red flowers appear during late summer and into autumn and in their homeland are attractive to hummingbirds. The plant, which can vary in height and spread from 60-90cm (24-36in), succeeds in a sunny spot in any dry well-drained soil, and only requires occasional irrigation. It is suitable for USDA zones 4b - 8.

Sporobolus wrightii

The final plant from these selections to mention today, is one with which I am unfamiliar, although it looks great and would appear to have tremendous future when word gets out amongst trendy garden designers. This is the Giant Sacaton, Sporobolus wrightii, a tough drought-tolerant ornamental grass. The ochre seed heads can reach 1.8m (6 ft) in height and continue to provide interest through the winter. It grows well in any average soil, only requiring occasional watering during really dry periods. It is suitable for USDA zones 5 - 8.

Globe artichoke

When considering gardening under dryish conditions, amongst the first plants to come to mind are the Cynara species - cardoons and globe artichokes. Although I personally think that the globe artichoke is a bit over-rated as a vegetable, it is undeniably a fine plant for the ornamental garden and can be comfortably accommodated in the mixed or herbaceous border. It is a tall plant, when producing its flower buds, growing up to 2m (78ins) depending upon cultivar. It has deeply cut bluish-green leaves, up to 90cm (36in) long that are produced from a crown that gives the plant the appearance of a giant decorative thistle. Globe artichokes are usually purchased as off-sets and planted during mid to late spring. These are the outer divisions from an established clump. Sometimes they are from plants known as "globe artichokes" which have resulted from constant cultivation and selection, other times from named cultivars like ‘Vert de Laon’. Whenever possible choosing a cultivar is to be preferred. Seed raising is a possibility, the young plants being of similar size to off-sets in their second year. The disadvantage with seed raised plants is that they show wide diversity in stature and quality, mostly not for the best.

A bright sunny position and a free-draining but richly organic soil is essential for globe artichokes. After planting they must be kept well watered until established. Where more than a single plant is grown, allow a minimum of 90cm (36in) between plants in any direction. In the vegetable garden globe artichokes should be regarded as a long term crop, plants being allowed to remain where they are for five or more years without disturbance. Cultivation is confined to keeping the ground clean around the plants and tidying up faded foliage and flower stems at the end of the season. Do not cut healthy foliage back in the autumn, as might be prudent with other herbaceous plants, but allow the leafy growth to remain to protect the crown. In very cold areas it is usual to protect over-wintering globe artichokes with straw. The 'globes' are ready to harvest mid to late summer and are really the immature flower heads of the plants.

Whitefly control

Globe artichokes are inextricably a part of southern European life, as indeed are roses. In the Campania region of southern Italy there is a great move to producing roses 100% biologically without the intervention of any chemicals. Some 200 hectares (495 acres) of cut flower roses are produced in the region and tremendous strides are being made towards achieving this objective. One particular element in this biological control programme, which has potential future benefits for the home gardener, is the use of a clone of tobacco that has a very low nicotine content. Flying insects, such as aphids and whiteflies like to feed on these tobacco plants. The pests are controlled in a simple focused way by the tobacco plants being inoculated with the predators (Macrolophus caliginosus for white flies and Lysiphlebus testaceipes for aphids). The tobacco plants are spread around the greenhouse amongst the crop.


Eryngium 'Blue Glitter'
This is a great new border or cut flower perennial with steely blue stems and flowers. It grows 90-100cm (35-39in) tall and enjoys an open sunny, well drained position.

Begonia Non-Stop - ‘Mocca’ series
This is the only dark bonze-leafed series of Begonia that is uniform and early flowering. These cultivars produce large 10cm (4in) diameter, fully double blossoms in five colours (yellow, orange, deep orange, scarlet and white). These all contrast well with the dark leaf colour. They are ideal for pots, baskets and bedding use.

Cat Series Pansies
The latest in the series of pansies known as Cats, is the startling ‘Cats Orange’. It is a compact, well-branched plant with a long flowering period, and is ideal for container gardening.


East of England Garden Show
The Wood Green Animal Shelter,
Website click here.

Happy Gardening



Today’s Sponsor

Colorado Plants: Plant Select
Globe artichoke: Wikipedia
Whitefly: USDA
New Plants: Benary

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