13 July 2015

Stonecrop Identification (Biting, English, and White)

Note: The following appeared on the St. Giles Living Churchyard blog last year and can be read in full here.

July saw all three of our stonecrops in flower; the biting stonecrop, english stonecrop, and white stonecrop. In the past when I've seen english stonecrop and white stonecrop in isolation, I've sometimes struggled to reach the correct identification, so let's have a look at our stonecrops and see the distinguishing features are when compared to other common Sedum species.

Biting Stonecrop

This is our only yellow stonecrop and it's a perennial, which immediately rules out annual stonecrop (Sedum annuum) which at most is biennial. Being a low mat-forming plant, we can see that it's not reflexed stonecrop (Sedum rupestre (S.reflexum)), which grows up to 30 cm tall and has its' yellow flowers clustered on an umbel-like stalk.

White Vs. English Stonecrop
Now, it's with these two species that I can sometimes become unstuck. They are both mat-forming evergreen perennials and both grow in similar conditions (rocky ground and stone walls) and flower around the same time of year (June to September). Let's see photos of some features side-by-side and see what the differences are.

The photos below show the leaves of each stone crop.  We have English stonecrop (Sedum anglicum) to the left with pale green to red leaves that are often described as 'egg-shaped'. To the right is White stonecrop (Sedum album), with (what looks like to me) fuller green to red leaves that are often described as 'cylindrical-oblong'. On both species the leaves are alternate. In the books I have (see references below), which have illustrated rather than photographed images the English stonecrop tends to be shown as the plant with red leaves, with white stonecrop being shown as having primarily green leaves. This may well depend on the time of year and the population being observed.

Our english stonecrop has 6 petals, which seems quite common, but often both species are described as having star-shaped flowers with 5 petals per flower that are white or pink tinged. On our specimens we can see that the pink tinge is more easily seen on the white stonecrop with our English stonecrop showing a yellow tinge in the centre.

Finally, let's have a look at the stems. The stems of the English stone crop have large hairless leaves growing alternately up the stem, which rules out thick-leaved stonecrop (Sedum dasyphyllum), which is very similar looking.
The leaves of the white stonecrop remain cylindrical and have a much brighter and shiny look to them.

Writing this has certainly helped me get to grips with these two species and I hope it assists anyone who stumbles across this post! It's important to remember that there is always variation within and between plant populations, but using a botanical key like that in The Wild Flower Key by Rose and O'Reilly will help you understand which features are important when identifying your plant.

06 July 2015

Book Review: Wild Flowers by Carol Klein

This book takes us through the seasons looking at some of the wild flowers that grow throughout the UK countryside and at the cultivars that have been bred from them.

Carol's writing is wonderful and within a few short pages we get social history, botany, life stages and photographs of the wild type as well as some of the cultivars mentioned in the book.

This is the first Carol Klein book I've actually read, and I find that she writes in the same infectious, excitable and intelligent way that she talks. She has a real passion for plants and writes a lot from her experiences in growing the plants she talks about in this book.

I'd be surprised if there's even a single reader who doesn't come away from this book with a desire to grow at least a hand full of the species and cultivated varieties described in this book. Carol helpfully tells us which are invasive and provides some good planting combinations.

The only downside is that Carol is being treated as a brand in this book. Her name is where the title ought to be and barely a couple of pages go by without a photo of Carol instead of all the magical cultivars described but not given even a quarter page. This can make it hard to follow the writing because there's no visual to guide the way. But, even so, this book is worth a read. My only hope is that Carol comes back with a much more detailed and plant photo rich book that will rival Flora Britannica - but for gardeners!

29 June 2015

Trunk of the Month: June 2015: Acer griseum

Acer griseum is also known as the paperbark maple. This is because the bark on this beautifully ornamental tree peels away in decorative curly flakes; in a similar way to the birches.

Sadly, this tree is on the IUCN Red List with a status of endangered. While the paperbark maple is found naturally over a wide area of central China, the population is small and fragmented. It is aid to be difficult to propagate whether by vegetative methods, such as cuttings, or by seed.

Unsurprisingly, this tree has the RHS Award for Garden merit and its green leaves turn red and orange in the autumn. Growing to around 12 metres high and 8 metres in spread over 50 years, a large garden would be required to get the best of out of the tree, but if I could meet the criteria, I'd definitely grow it.

The only problem with this trunk is that nothing of note seems to be growing on it or using it as a habitat. But, that being said, you can't have everything. The beauty of the trunk alone makes this my trunk of the month.

Kew. (n.d). Acer griseum (paperbark maple). Available: http://www.kew.org/science-conservation/plants-fungi/acer-griseum-paperbark-maple. Last accessed 28/06/2015.