One of the delights of late Autumn is seeing the daphne velenovskyi putting forth a few late flowers for the withering hours of the aniline light of November. Most of its leaves have fallen, but this fading burst of life, can make one stop and admire'so different from the gaudy spectacle of May when it's blooms overpower all the new green growth in a robe of pink. Whatever is the plant thinking! It freezes solid at night (20 F); but, the flowers never brown or drop. I mentioned this to Josef Halda once, who replied succinct manner, "...where it grows, it freezes every night." It seems ridiculous to assign a 'cold hardiness' rating to such a plant. Growing at 3000m in the Pirin Mt. of Bulgaria, it may even survive the magic number of -40 F, though I don't know. It is one of the slowest growing daphnes, and takes well to any spot that is well drained. I tried growing it on tufa, but the plants did not like the constriction. I do think it would thrive in a clay crevice between rocks. In the garden we have plants in full sun, facing south and also on the opposite slope in considerably less light with little difference in flower production or growth.
Equally hardy, but entirely evergreen is the larger d. arbuscula and the derivative clones now offered - we have 4 ourselves. The smallest of these, d. arbuscula 'Muran Castle', is a compact mound of the most verdant green one can imagine. Flowers are a pale pink and abundantly cover the plant in May. This clone has the distinct habit of rooting from the branches that touch soil - not all forms do this- and these branches can be separated and used for new plants.
Rick Lupp offers a form, d. arb. 'radicans', which is also quite dwarf. However, the needles are shorter and remind one of close relationship with d. petraea. By the way, d. arbuscula will brow in tufa quite well- not too surprising as it is a true chasmophyte
A curious form of d. cneorum 'porteous' came by way of Barrie Porteous, which he believes is a dwarf form from the French Pyrenees. Completely prostrate, it looks more like a small willow with the red/brown stems exposed as it gets older. Typical white, very fragrant flowers adorn the branches. This plant is small enough to use in containers. Like d. velenovskyi, it does not grow in tufa well, but needs a coarse soil.
The hybrid d. arbuscula x d. collina named d. x 'Lawrence Crocker' is possibly the easiest of all daphnes available now. An intermediate form with gray/green leaves, dark pink/purple flowers of d. collina and is wonderfully fragrant. A bit larger than d. arbuscula it grows eventually 20cm tall and 30cm wide. It is easily controlled by cutting it back severely. This is, in fact, the best method for encouraging healthy growth and second bloom) and can be done to all daphnes.
Of the smaller hybrids now available, I like d. x thauma (d. petraea x d. striata) as it has a moderate growth rate and the white flowers are set off by the dark green leaves.
Daphne x whiteorum 'beauworth', a cross of d. jasminea and d. petraea has large red/pink buds, opening to rose pink flowers. An easy growing plant with dark green leaves, it forms an attractive multi-branched shrublet.
Another compact mat is d. x 'schlyteri', with parents d. x 'leila haines' and d. arbuscula - it retains the darker flowers of d. x 'leila haines'. It can be used as a low spreading mat. A regimental clip will encourage new growth and more flowers.
Daphne hybridization is very active and new intros are soon coming. I like especially the one's that Rick Lupp has created. He is very selective and names only the best. Two of these are named for his granddaughter, another for the superb plantswoman Ev Whittmore. They are worthy specimens for any rock garden.
I have always been interested in how daphnes will grow on/with tufa and have found it is best not to make assumptions- the response is quite individual. However, there is great promise in growing the smaller daphnes in narrow crevices, sandwiched with a clay/sand mix. In early April Halda planted some troughs for us in this fashion and though it froze solid every night for over a week, even the d. calcicola was unfazed - and everything was straight out of the green house. Since Halda and others have used this method for well over 20 years, it is time we in North America adopted it too. The best aspect of this method is it provides a less stressful environment for root growth, and almost as a bonus, the design and display possibilities take a quantum leap. There will more on this next spring.