Quite hardy in the UK this easy orchid which is native to Madeira, can grow to 30", (75cm) tall and is a splendid sight in early summer with its magenta to purple 6"-15" (15-40cm) spike of large flowers. This orchid will grow in quite a range of positions from semi shade to full sun providing the moisture supply increases accordingly. It wants an open, free draining, moisture retentive compost, and is equally happy in a deep pot or in the open garden.
The reason for the name, Dacty (finger) Rhiza (root) is immediately apparent as soon as you see the tubers. The new tuber is produced at the end of the growing season as an appendage to the old tuber that produced this years flower spike in mid to late May. As the flower fades and sets seed the old tuber withers away leaving usually two replacement tubers, these are each about the size of a baby's hand and initially have short tapering roots as fingers that elongate during the winter and by spring may have reached 10" (24cm) each.
In pots, I use equal quantities John Innes no 3, cornish grit and a multipurpose humous rich compost. The plants are repotted every year, either just as the flowers are going over(July) or in the spring(March) just as they are coming back into growth. If grown in the open ground the best time is in July as little or no damage is done to the new roots, the plant should be lifted, shaken off and the new tubers twisted off from the old. These can be planted where required with the tip just below the surface and topped off with a little grit. The old plant can be deadheaded and replanted as occasionally additional small tubers may be formed. Equally, the plant can be left for several years and only divided when either pot bound or congested, in this case a quarter strength liquid feed applied a few times during the growing season will not go amiss.
If required, a single capsule of seed is ample under ideal conditions to produce a thousand plants, however orchids seed is exceptionally fine, has no energy to support the embryo on germination and so the plant depends on a symbiotic relationship with a group of fungi to feed the newly germinating seed. This fungus is usually abundantly present in the old compost so it is a good idea to spread this on your sowing surface and sow the seed directly onto that. Invariably however, seedlings will turn up elsewhere in the garden, usually in the most unlikely places, often, in pots of primula or other seedlings where the compost has been kept just moist.
These make splendid garden plants, are an easy introduction into the world of hardy orchids and are becoming more readily available each year. Although initially a little expensive, your single purchase should multiply into a dozen flowering plants in three years with some additional small non flowering tubers to give away or swap for some of the many other British native hardy orchids.