WOODLAND (Shade tolerant) PLANTS at OpdeHaar gardens

Perennial woodland plants

Podophyllum Spotty Dotty
Podophyllum Spotty Dotty

This section of the website is about the shade loving, flowering, perennial woodland plants which are growing in our woodland garden at OpdeHaar in The Netherlands. Perennial woodland plants by definition are shade tolerant. Fortunately, our woodland is mainly moist and we have few places where we have to cope with dry shade. Also, our wood is noticeably cooler on a hot summer day than the rest of the garden. On the other hand, in winter the trees provide protection from frost.

Perennial woodland plants flower mainly in the spring before the leaves on the trees provide a denser shade cover. However, there are some notable exceptions, such as begonia and impatiens.  In fact, a woodland garden can be enjoyed throughout the year. It starts with the spring bulbs, snowdrops, bluebells and narcissi (see bulbs). In summer there is a cool canopy of leaves overhead and in late autumn the floor of the wood is often covered in  mushrooms and many trees are showing their autumn golds, reds and yellows. (See trees).

In contrast to many other areas of a garden a woodland is made up of 3 layers.  The perennial woodland plants are on the ground. While shrubs, such as holly, rhododendron, camellia and skimmia  form the middle layer. The upper canopy is the trees such as acers, magnolia, silver birch, beech and oak.

For information on planting in a woodland, click here.

Woodland plants – shade tolerant – why?

Click here to learn why some plants are shade tolerant. It is helpful to know the basic botanical principals of photosynthesis and plant nutrition in order to better understand the behaviour and needs of plants grown in either sun or shade. I have chosen to include this summary as an introduction to shade-tolerant plants. Shade-tolerant plants have adapted their prime food-making mechanism (photosynthesis) to reduced levels of sunlight (the energy provider of this process).

Perennial woodland plants at OpdeHaar

Epimedium grandiflorum Lilafee - a perennial woodland plant
Epimedium grandiflorum Lilafee

On this page you will find information on and/or photos of anemone, aralia,  begonia grandis, calanthe, chloranthusepimedium, helleborusimpatiens(bizzy lizzy) mosses, mushroomspodophyllum, dysosma, polygonatum, (smilacena, disporum, disporosis), pulmonaria, rohdea, selaginella, tiarellatrillium and more woodland plants.   

Under Miscellaneous there are photos of the following plants: allium ursina, arum, asarum, chrysosplenium, cornus, deinanthe, diphylleia, hacquetia, hepatica, lamium, lysichiton, mandragora, mertensia, mukdenia, omphalodes, pachyphragma, peltoboykinia, pollemonium, rabdosia, rubus,sanguinaria, saruma, soldanella, tricytris,uvularia, vinca. 

Don’t forget to look at aroids, araceae, hosta en ferns – also woodland and shade tolerant plants.

All of these plants can be found in our woodland garden

All photos were taken in our garden. Click on the photos for a larger image and a slideshow  

Anemone

Aralia

Begonia grandis

For information about Begonia grandis ssp. Evansiana and other winterhard begonia hybrids click here

Calanthe

Chloranthus

Chloranthus are woodland plants which are fairly well known in Japan and S.E.Asia.

For more information on chloranthus, click here.

Epimedium

Epimediums come in many variants. The photos here show a fraction of what you can see at OpdeHaar. Most are happy in shade and generally cope well with dry conditions. They spread by rhizomes. Indeed some, such as the E.X youngianum hybrids, are vigorous enough to be considered as good groundcover candidates. The old leaves can be clipped off in early February to render the Spring flowers better visible. You can do the Hellebore leaves at the same time! Wikipedia gives a quick review of the genus but the standard text is W.T.Stearn’s “The Genus Epimedium” (ISBN 1 84246 039 0).  This book also covers other members of the Berberidaceae family, notably Podophyllums. It is therefore useful for the shade/woodland gardener.

Epimediums also have medicinal uses in traditional Chinese medicine. Indeed there is more on this on the Internet than on their role as garden plants!

Helleborus

There are a variety of different species of hellebore – a typical woodland plant and harbiger of Spring.  These colourful plants, together with snowdrops, herald a new gardening year. The flowers of the natural species do rather “hang their heads”. Increasingly various selections and hybrids are available where flowers are more visible and outward facing.  

Helleborus Christmas Carol - a perennial woodland plant
Helleborus Christmas Carol

For more information on hellebores, click here.

Impatiens (Bizzy Lizzy)

 

Impatiens omeiana
Impatiens omeiana

Having talked about hardy begonias, it seems fitting to introduce the hardy version of “Busy Lizzy”. It is, of course, more grandly and correctly, known as Impatiens omeiana. This plant was originally found in 1983 by Don Jacobs on the famous Omei Shan (Mount Emei) in S.E. Sichuan, China.

It is a beautiful foliage plant which grows to around a foot high. It excels in moist shade and slowly forms a clump. it is therefore ideal as a woodland plant. Yellow trumpet-shaped flowers appear in autumn but, like begonia, it is really a plant which one grows for its foliage. It is also hardy in our winters in The Netherlands. Despite this and it’s ease of propagation, it is still a bit of a rarity in the Dutch nursery trade. Unfortunately it isn’t yet seen in garden centres.

At least two variants are reported by specialist nurseries. In “Ice Storm” the attractive leaf variegation is rather masked by a sort of haze over the leaf. To my mind, a far more attractive and currently rarer variant is a dark leaved, variegated variety called ”Silver Pink” or ”Silver and Pink”.

For more information on Impatiens, Click here

Mossen 

Moss en boomstam

We have several different sorts of mosses in our garden. All mosses have stems and leaves, but no roots, just stems which carry hairlike appendages called rhizoids which hold the moss onto the substrate on which it is growing. Mosses absorb water with dissolved nutrients primarily through their surfaces but can also obtain nutrients by forming symbiotic partnerships with soil fungi. Although some mosses do contain some lignin, it is not sufficient to give moss stems the rigidity to counteract the forces of gravity and grow vertically when free-standing. In short, their internal structure and workings are different to those found in vascular plants, They reproduce by means of spores and this same mechanism is present in ferns. Internet and sources such as Wikipedia provide deeper insights –  https://en.wikipedia.org/wiki/Moss .

There are 3 important sorts of mosses – leafmoss, livermoss and crustmoss. Often all 3 sorts are seen in the same area. 

  • Leaf mosses form spores in caps. The spores are either slung through small openings or they are released via 4 splits. However, the spores are more usually dispersed through an opening in the mouth which becomes visible when the cap has fallen off.
  • Livermoss are either flat and lobed or they have small leaves in 3 rows. 
  • Crustmosses are formed from mould in close relationship (symbiosis) with another plant.

 

 

 

 

Mosses growing on tree stumps  Haircap moss (Polytrichum commune), cushion moss (leucobryum glaucum), greenshield lichen (parmella caperata)

One indicator of the health of the woodland is the mosses. We have quite extensive carpets of moss, which we are protective of. However, during hot weather, they shrivel and appear dead, but with a few drops of rain they spring back to life. Unfortunately, with global warming, our mosses are suffering during the very hot, dry periods which are becoming a feature of our summers in recent years. Chinese botanists have also signalled a similar phenomenon and commented that one moss which has adapted to dramatic climatic changes since the dawn of time now seems unable to cope with current high rates of global warming – https://www.japantimes.co.jp/environment/2023/08/25/wildlife/warming-kills-million-year-moss/ .

Mushrooms

We are certainly no mushroom or fungi experts. However, every autumn, particularly after wet weather, we find all sorts of mushrooms in the wood. I hope that the identification is correct, but don’t trust it. Mushrooms such as sulfur tuft (Hypholoma fasciculare),  the shaggy ink cap (Corprinus comatus), oyster mushroom (Pleurotus ostreatus)  and  turkey tail mushroom (Trametes versicolor) grow on dying wood but do not attack living wood.

Podophyllum and Dysosma

Podophyllums are ideal foliage plants for moist, lightly shaded positions and are perfect subjects for woodlands. 

There are several other Asian Podophyllums with the general characteristic of highly decorative leaves. These are still often found under the nomenclature “Dysosma” rather than “Podophyllum“.  These highly decorative Asian podophyllum varieties are generally expensive. Furthermore, in my experience, they are rather more temperamental than their plainer family members. That said, garden visitors often stop and comment on varieties such as P.veitchii (P.delavayi) and P. difforme. 

Podophyllum “Spotty Dotty is shown in the photos. It is a highly decorative plant.   “Spotty Dotty” is a lovely addition to the woodland garden and here at “OpdeHaar” is as temperament-free as P.peltatum.

For more information on Podophyllums, click here.

Polygonatum, (smilacena, disporum, disporosis)

Pulmonaria

Rohdea

I can safely say that if you do come across a plant label bearing the name “Rohdea“, I would seriously consider buying it while you have the chance because you most probably won’t get another opportunity very soon! This is certainly so in Europe although in the USA, the plant seems to be better known but it is still a comparative rarity. This state of affairs is in marked contrast to Japan where new Rohdea cultivars enjoy a collector’s status comparable with that enjoyed by the latest Hosta varieties by collectors in Europe and USA. In fact, this comparison can be usefully extended for Western gardeners by saying that Rohdea are evergreen candidates for planting in shady, dry spots where Hosta suffer from the lack of moisture or where slugs are a big problem. Visually, an established Rohdea creates a similar impression to that of a Hosta with the bonus that the thick, fleshy leaves are not only evergreen but resistant to both slugs and deer. Talking of slugs, one still encounters reports that slugs are pollinators of Rohdea (“malacophily” for pub quiz fans !). Although this century-old proposal has recently been demoted to myth status by investigations in Japan, it serves to underline the fact that, for once, slugs aren’t a problem for the gardener. Most plants encountered are Rohdea japonica and its named cultivars selected for the pattern and extent of creamy white variegation on their dark green, strap-like leaves.

 From the nurseryman’s perspective, Rohdea only grow slowly and are reportedly impossible to propagate by tissue culture; this combination means that saleable plants aren’t cheap. Propagation is by dividing clumps which form as the rhizome extends and seeds are produced. Seed propagation is not difficult but it isn’t for the impatient gardener. I harvested seed from R.japonica “Variegata” from a greenhouse grown plant which I purchased for its very visible seeds in April. I immediately washed the small, pea-sized capsules and sowed the cleaned seeds which all germinated after 8 to 10 weeks.  Seed propagation gives Mother Nature the chance to reward one’s patience with an interesting new leaf variegation so I can at least dream !

From my limited experience here in the Central Netherlands, winter hardiness hasn’t been an issue and this is echoed in the literature which also cautions that exposure to strong afternoon sun can be a problem. Rohdea really are plants for shady locations.

Taxonomists class Rohdea in the Asparagaceae family and if you imagine rearranging the red berry-like seed pods which are a decorative feature of Asparagus that has set seed  into the form of a small column  similar to Arum italicum seed stalks, then this is what you can expect to see on R.japonica plants as autumn progresses.  The spring flowers are white and very small but referring to them as insignificant is just a bit too dismissive.  Reference to Rohdea in Flora of China still remarks that it is a single species, R.japonica. However, a revision of the genus by Tanaka in 2010 has published data on 17 species with 10 endemic to and 15 to be found in China. Tony Avent and his team at Juniper Level Botanic Garden have published an excellent summary of the species, cultivars and a key to understanding the Japanese cultivar nomenclature along with a comprehensive photo gallery which is compulsory reading and a reference for gardeners who are interested in growing Rohdea.

Selaginella (Spike- or clubmoss)

Once upon a time about 470 million years ago, primitive liverwort-like plants had developed to cope with life on dry land. Their marine ancestors had already created chlorophyl which catalysed plant food production (sugars/starches) from carbon dioxide and water using energy from ultraviolet ( UV) radiation in sunlight. Emerging from the primitive seas, the plant ancestors encountered additional challenges to their further evolution which included exposure to damaging rays in the so-called UV-B spectrum and being able to literally stand upright under the force of gravity for which the sea had previously compensated. Over the next 25 million years or so, complex chemical reactions came into play including the development of a sunscreen chemical which could also form a rigid polymer (lignin) which, along with numerous other evolutionary modifications such as root systems, permitted plants to grow and thrive on dry land. Amongst the earliest land plants dating from about 425 million years ago on Gondwana are the so-called Lycophytes. During the Carboniferous period ( 360 to 300 million years ago) these developed into massive forests with plants up to 30m high and which formed our modern-day coal deposits (https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.16600 ). The massive lycophytes are extinct but smaller representatives live on to this day in the form of club mosses or Selaginella (https://en.wikipedia.org/wiki/Selaginella ).

Our interest in Selaginella is centred on plants which can be grown outdoors here in the Central Netherlands which are dramatically fewer than what is available to specialists using terrarium culture. General cultivation requirements are for light shade on acidic, humus-rich and moist soils and Selaginella helvetica from the Swiss Alps forms an attractive clump alongside our pond and is perfectly hardy. Visitors to Madeira can encounter vast sheets of Selaginella kraussiana in shady areas of moist woodlands alongside some Levada.

Selaginella helvetica
Selaginella helvetica

In my experience, it isn’t winter-hardy here although I have seen both it and a golden variant offered as “hardy selections” which I haven’t yet been able to verify. That said, I kept the golden variant in an unheated greenhouse a couple of years ago and it soon covered the large seed tray in which I’d put it so maybe I’ve just got to find the right spot in the garden. Last and by no mean least is Selaginella moellendorf(f)ii which glories in having the smallest known plant genome size yet reported and can be found from The Philippines to North Central China. Characteristically, Tony Avent ( Plant Delights) sums it up brilliantly as looking like a fern which has been run over by a lawnmower and so it does. The literature relates that it takes on a russet colour as temperatures drop in Autumn and that it survives minus 15 deg C but is then deciduous – it should be OK here but I need to wait and see.             

Here in the Netherlands, I haven’t found it easy to find Selaginella for sale in the nurseries. However, during a holiday in Costa Rica in December 2023, we stayed in a lodge in the cloud forest near the town of Uvita with a trail in a stream valley. During a 20 minute strole I came across numerous varieties of Selaginella adjacent to the path which goes to show that where conditions are right, these plants are easy to find – correct identification requires more skill!

Selaginella found by us in Costa Rica

Tiarella

  Trillium

Miscellaneous – More woodland plants – schade tolerant plants

Under Miscellaneous there are photos of the following plants: allium ursina, arum, asarum, chloranthus, chrysosplenium, cornus, deinanthe, diphylleia, hacquetia, hepatica, lamium, lysichiton, mandragora, mertensia, mukdenia, omphalodes, pachyphragma, peltoboykinia, pollemonium, rabdosia, rubus, sanguinaria, saruma, soldanella, tricyrtis, uvularia, vinca 

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