Iris foetidissima

After a brief diversion let's get back to plants for dry shade and it's another Iris for which I make no apology - I like Irises! This is Iris foetidissima. The specific epithet foetidissima means smelly, in practice this just means the leaves smell a little unpleasant if bruised, but its common name is the Stinking (or Gladwyn) Iris. This iris has evergreen fans of leaves and relatively insignificant flowers ranging in colour from yellow to purple. In the winter, however, the Gladwyn Iris comes into its own. The seed pods split to show a mass of brightly coloured seeds in shades of red orange and yellow. Cultivar 'Fructo Alba' has white seeds. Birds tend to ignore them so the display is long lasting. There are various cultivars apart from the one above. The species has flowers in various shades of purple, var. citrina has yellow and brown flowers, and 'Variegata' has green and white foliage. The latter is however not very free flowering.

Houghall Plant Centre is selling Iris foetidissima var. citrina from £2 a pot

Nothing to do with dry shade but I wanted to share this little beauty with you. This is Iris 'Katharine Hodgkin' (usually marketed as reticulata group but actually a cross between I. winowgradowii and I. histriodes) growing in the gravel plunge bed at Houghall. Iris reticulata is a bulbous spring flowering Iris native to Iran and Turkey which gives you some idea of the conditions it prefers - dry, well drained and in full sun. It spreads slowly by division (I have never known it set seed but it may away from north east England) which take two or three years to come to flowering size. There are many different cultivars, a quick google image will bring them up, 'Harmony' and 'Joyce' are two that spring to mind. They come in various colours but in my opinion 'Katharine' is the best of the bunch.

Houghall Plant Centre sells Iris reticulata bulbs in the Autumn

Snowdrop (Galanthus species)

An excellent plant for growing under shrubs and trees because it flowers, sets seed, and stores food for the following year before the leaves above it have fully unfurled. (Apart from one, Galanthus reginae-olgae, which is autumn flowering). Galanthus nivalis is the best for naturalising, it spreads by seed and offshoots to produce a white carpet in February. Most authorities suggest snowdrops are best planted in the green, ie while still in leaf, but I have found that bulbs bought from a reputable supplier, who doesn't allow them to dry out, can be successfully planted dry. Most garden centres sell pots of snowdrops in early spring which can be hardened off and planted outside. Plant dry bulbs at a depth of twice their size (a useful rule of thumb for most bulbs) and "green" plants at their previous planting depth. Clumps will need dividing and replanting when they become congested - a good indication is when the bulbs rise to the soil's surface.

Snowdrops such as 'Lady Elphinstone' and 'Magnet' need, I think, to be planted somewhere where their markings and scent can be appreciated so I would suggest a raised bed rather than under shrubs/trees. Any good gardening encyclopedia will show pictures of the snowdrop cultivars but be warned - some of the rarer types sell for over £100 a bulb!

Houghall Plant Centre is selling snowdrops (species and cultivars) at £1 to £5 a pot

DRY SHADE

One of the big problems in any garden is planting in the shade cast by trees and large shrubs. Not only is there a problem with lack of water but also light levels are low and the soil lacks nutrients. The first recourse is to mulch the soil with either good garden compost or well rotted manure. This will add nutrients and the organic matter will hold on to the water. At this point I must say that if your problem is a large evergreen, give up trying to grow things under it and disguise the base either by planting shrubs and perennials outside the drip line of the foliage and/or by planting climbers away from the tree/shrub's roots but with the support angled towards it. Try to match the vigour of the climber with the size of its host though.
Some trees are allelopathic, i.e. they produce chemicals which inhibit seedling germination and growth. Walnut (Juglans species) is a well documented example but research into this is continuing and many plants may well have similar protections. (A possibility here for an organic weedkiller?)
You may well be contemplating an irrigation system at this point. I would suggest a completely different approach. Now that nutrients are available look for plants that actually enjoy these conditions.Next time I'll talk about these plants - there are quite a few, honestly!