Firstly a heartfelt plea for more articles. As we move into the winter months it is difficult to find fresh material, but please tell us about good gardens or nurseries you visited this year, or fine plants you have seen. Send items to wasjsime@gmail.com

Plant of the Month….. Tricyrtis (Toad Lilies)

These plants come into their own in autumn, when there is not much else in flower in the shade garden. They put on a display of intricate, otherworldly flowers. There are about eighteen species and are all woodlanders from east Asia, mostly from Japan and Taiwan. They are said to be easy to please, providing you have a good woodland soil that does not dry out in summer. I have not found them quite so easy, losing several plants to slugs and snails long before they can get big. Where I have been successful they have either been largish plants when put out, or were vigorous hybrids such as ‘Pink Freckles'. They grow reasonably easily from seed if sown when fresh, but, as just remarked, grow them on well in slug free pots before planting them out. Large clumps also divide easily in the spring. The pictures show three of the best growing for me: ‘Pink Freckles, formosana, the basic form and the selection ‘Purple Beauty'. I also have an expanding clump of T. hirta grown from seed from the distribution. Here it seems to flower earlier than the others, and the seed pods are well developed

T. ‘Pink Freckles'
 

Tricyrtis formosana
 

Tricyrtis formosana ‘Purple_Beauty'
 

I have tried three times to grow T. macrantha subsp. macranthopsis. This is a beautiful plant with large, bell-shaped, pale yellow flowers with red spotting on the inside. The stems are a bit droopy, but dangling over a wall they look fantastic. In all three cases I think I lost the plant to slugs. If I try again it may stay as a pot plant where it can be protected with slug pellets. T. oshumiensis is similar, and at least produced flowers before becoming slug food.(see photo)

Tricyrtis oshumiensis

Climbers for Shade Part 4: Pileostegia viburnoides

I was prodded into dealing with this plant by the following note from Sue Ferguson.

“Pileostegia viburnoides at Picton Castle.

“I'm sure most Woodland and Shade group members will know the self-clinging climber Pileostegia viburniodes – fantastic for a north wall and flowering with fluffy panicles of off-white flowers in early autumn. Probably many of you will be like me and have a plant you rather take for granted on the north side of your house or similar doing its modest thing at a quiet time of year in the shade. If so, you must go and see the one at Picton Castle in Pembrokeshire.

“I went on the 1st October this year as part of a fern group visit and was knocked out by it (not literally you understand). It's been there well over 30 years and is growing up a large oak tree. It's clothed in leaves and flowers right from the trunk of the oak to its topmost branches, but the main display was on the top of the upper branches, where it was flowering in huge swags and swathing the tree in its blossom. An example of how a plant you have rather overlooked can suddenly show you what it can do when given a chance – perhaps if I move mine to an oak tree I might just see it in its prime!

“Picton Castle is a fine garden and, even if you weren't there in October to see the Pileostegia, has much to interest the shade gardener and is well worth a visit if you are holidaying in West Wales.”

Pileostegia viburnoides

Pileostegia is a genus in the family hydrangeacea. There are two species: P. viburnoides and P. tomentela. The later is not in general cultivation. “Flora of China” says that it is like P. viburnoides, but hairier! The plant is easy to grow against a wall or up a tree providing the soil is neither waterlogged nor too dry. I include a picture of a plant from my own garden, but not even approaching the size and flower power of the one described by Sue. It roots easily from cuttings, but growth is slow, and this is one of the few plants for which I would recommend buying a big one if you can afford it. The extra years are worth the money.

‘Dry Shade' Part 1

In response to requests from a few people I will try to write something about dry shade, although I start with the caveat that I have a reasonably moist garden, and do not suffer too badly from the problem, and so a lot of what I will say will be book learning and not experience.

I think the reason it is a perennial problem is that simple ‘dry shade' does not exist and the question ‘what do I do about dry shade' needs to be unpicked a bit.

When people ask the question they can mean many things varying from. ‘I am a lover of woodland plants and want to grow more and more interesting plants in my dry areas' to ‘My main interest is my sunny herbaceous borders, but I want my shady areas to look presentable.' There is obviously a real difference in the amount of time and effort each of these questioners is willing to put into the problem and an answer for one would be no good for the other.

There are also real differences in the types of dry shade that occur in gardens, each with its own horticultural problems and opportunities. For example there is the world of difference between a border to the north side of a leylandii hedge and a bed under a mature oak. To try to get to grips with these differences we need to recap some basic horticultural principles. This will be old hat to many of you, but it will help to make sure we are all starting from the same place.

There are many factors that govern how well a plant will grow, but they all come down to the question of whether it can produce more carbohydrate in photosynthesis than it needs to burn in respiration to keep itself ticking over. The excess can be used to produce more leaves, stems, flowers, seeds etc. In shade two major factors determine this. Firstly is there enough light of the right quality falling on leaves to provide the energy for the process and secondly, is there enough moisture to keep the tissues turgid and allow transport of the various chemicals involved.

Two types of light hit the leaves of plants grown in shade: firstly, diffuse (back-scattered) light ‘seeping' in from the world outside and secondly direct light coming either when that part of the bed is in direct sunlight or breaking through the canopy as light flecks. The plant can use both, but the former is thin gruel compared to the latter, and many shade-adapted plants can accelerate their photosynthesis when light flecks fall on them. Thus whether an area of shade has a deciduous or an evergreen canopy, or, if it is to the north of a wall or hedge, how tall the hedge and close the plant determine how much high quality light is available.

The question of moisture is also complex. Most woodland plants are relatively shallow rooted. It is seldom that their roots go below 6 ins or so. There is no point going down for moisture, the tree roots are there! So a major factor in water availability is the water holding capacity of the top 6 ins. The soil must be humus rich and well protected by a mulch. In the wild both are provided by the falling leaves of the canopy trees. Plants from different parts of the world are adapted to having available moisture (and hence growth period) at different times of the year. All are adapted to free draining soils and very few can put up with water logging (not enough oxygen in the soil for the roots to ‘breathe'). Knowing what moisture is available and when is key to choosing the right plant.

In summary, to answer ‘What to do about dry shade?' we need to define how much effort we are willing to give to the problem, and what sort of shade (light and moisture level) we are dealing with. In future parts of this series we will deal with four cases of shade type (very dry, very dark; not so dry, very dark; not so dark very dry, and not so dark, not so dry). For each we will consider options for “involved” and “low maintenance” gardeners and hence the types of plants that can be considered.

Shade Charades

Guess the species.

Two words:

The solution to last month's puzzle was Cardamine bulbifera. Cardamines are useful woodland plants, but make sure that you want this one before you plant it. Not only does it produce runners, but as the name suggests, lots of little bulbils in the leaf axils. It is pretty enough with pinkish flowers, but there are much better choices if space is limited!

Joe Sime

The HPS Shade and Woodland Plant Group is open to all members of the Hardy Plant Society. Please follow this link for more information.