Extensive and authoritative, the Royal Horticultural Society's (RHS) website is packed with green-fingered gen for the energetic gardener. It includes a plant finder, help-and-advice section, online shop and gardening calendar. The top 10 jobs you should be engaged on instead of reading this include: hoe borders, pinch out side-shoots on tomatoes, harvest lettuce, cut lawn once a week...
A prodigious resource for the garden visitor, this site provides maps for 10 parts of the UK, each with 30 or more gardens. Click on the garden you fancy and you geta page of information including photo and link to the website. Most popular pages include RHS Wisley, Great Dixter, Harewood House... Also includes section on great garden designers and directory of gardening websites.
This flashy website (twittering birds, clever animation) on the Lost Gardens of Heligan at St Austell, Cornwall, attempts to be simultaneously languorous and vigorously commercial. It includes slightly vertiginous virtual tours (the melon yard, vegetable garden, Italian garden and sundial) as well as an extensive online shop (crafts, toiletries, beeswax products etc.). There is also a timeline of Heligan and live webcams.
Information on the National Gardens Scheme (NGS), more commonly known as the "Yellow Book", which enables plant lovers and the plain curious to enter 3,600 mainly private gardens for a charitable donation. The NGS has raised £22 million in the last decade. Tap in your postcode and you'll find open gardens within 5 to 50 miles of home. The Scottish equivalent can be found at gardensofscotland.org
Currently offering 800 varieties of bare-root roses for delivery between November and April, the David Austin website also offers advice on which to buy for various locations in the garden and (surely most important of all) fragrance. Gertrude Jekyll, Charles Darwin and Jude the Obscure are among treats for the nose.
If you haven't visited the new 18-metre-high Rhizotron and Xstrata Treetop Walkway, you can experience a virtual peep on the Kew website. Other features include web pages of Kew's 19 science teams (the Madagascar page is worth visiting for the baobab trees), details of the 70,000 plant specimens in spirit and Decimus Burton's 4,880-sq-metre Temperate House from 1860.
Founded over 150 years ago, Thompson & Morgan offer a dizzying range of mail-order seeds from abutilon to zucchini. Current top sellers include the polychrome sweet pea Flying the Flag, the spinach Bordeaux and the aubergine Calliope, but some of us are tempted by The Spice Boys range of basils (cinnamon, Greek, lemon, lettuce basil etc.): 1,500 seeds for £3.99.
Experienced gardeners may find the style a little patronising, but there's no denying the extraordinary range of the BBC's online garden. Informative features include planning a vegetable garden, gardening for wildlife, gardening with children and a gruesome A-Z of pests and diseases, including powdery mildew, two spot spider mite and the fearsome-sounding thrips.
The website of Great Dixter, a riot of colour created in East Sussex by gardening iconoclast Christopher Lloyd, gets the pixels
of your computer in a right old tizzy. Displays of orange, red, purple and white erupt like fireworks. This would be among the most beautiful of all gardening websites if the captions were to one side rather than overlaying the photos. You need to visit the garden to get the full picture.
Doyenne of the herb world, Jekka McVicar won her 11th consecutive gold medal at Chelsea this summer. Her prodigious online catalogue boasts 48 pages of organic plants and seeds, including such wonders as banana mint ("peppermint with a hint of banana") and the ginkgo tree ("grows up to 40 metres") used in the treatment of asthma.
This impressive guide covers every aspect, from garden centres and specialist nurseries (there are 22 listed under "bamboo") to outdoor furniture and garden designers. If you want topsoil, a hammock, an artificial lawn, a hot tub, humane animal deterrents or information about gardens to visit in Jamaica, this is the place to look.
These relentlessly jolly eco capitalists have expanded from the Can-O-Worms compost wormery (£101) to heritage seed potatoes, a vast range of wild flower seeds, Duchy of Cornwall hand tools and "vintage" clay pots. You can download a Wiggly podcast too.
Her rambling gardens – gravel, scree, water and woodland – richly merit a visit if you're within reach of Elmstead Market, Essex, but Beth Chatto also has over 2,000 different types of plants for sale, mostly herbaceous perennials, on her website. Minimum plant order £20, no delivery before September.
All who saw Downderry's gold medal-winning lavender display at Chelsea will have been bowled over by the beauty, aroma and astonishing variety of this most appealing plant. You can download a catalogue from the website or make online purchases. The 16 frost-hardy lavenders sold by this Kent garden include the impressive Fathead, a cultivar introduced by Downderry in 1997.
Stapeley Water Gardens near Crewe is a mecca for those who like their gardens to be on the (very) damp side. Items on the website range from a 218cm tiered fountain (£2,999.99) to ramshorn snails (£5 for 10) that "rasp algae" from leaves. Water lilies are available in all five colours – white, red, pink, yellow and copper (12 cultivars in white).
Impressively lucid website with excellent range of hardy plants for sale by mail order, including 250 different types of bearded and 160 herbaceous peonies. Austin's comments are impressive for their honesty; one member of the "somewhat invasive" valerian family is described as "a true thug, especially in damp soils".
The gorgeous website of this Chelsea gold medal winner includes summer-planting bulbs, such as autumn-flowering crocus (from £3) and five types of amaryllis, plus 350 cultivars for autumn planting. The page of growing tips from these Somerset experts will help expunge the possibility of the dud bulb.
Offering 3,500 plants and bulbs, this impressive online shop has, for example, four pages of alliums and three pages of narcissi and tulips. The photographs are exemplary and accompanied by growing notes of admirable objectivity: "Trillium... are long-lived and trouble-free but a good display is for the patient gardener."
Containing details of 3,230 varieties (1,400 of them illustrated), this clematis site from the University of Hull is a fabulous resource about these exuberant climbers. It also carries information about pruning, diseases and clematis gardens, though some may feel that 24 web pages on clematis devotees borders on the obsessive.
This website is aimed at the less horny-handed end of the gardening spectrum – they need to be well-heeled if they're going to snap up such "best sellers" as a Padre set of garden furniture in artificial stone (£949) – and you'll need six people on hand to help the driver unload it.