The saying that ‘a little knowledge can be a dangerous thing’ certainly holds true in the world of horticulture.
As in many fields, the more you know about a subject, the more you come to realise that you have only scratched the surface.
I remember once serving a young couple who were keen to buy some plants for their first garden and had brought ‘Father-in-law’ along to assist. I selected a few suitable plants for their, quite small, plot, including a new cultivar of Cotoneaster. ‘Cotoneasters grow huge’ I was told by the self-styled ‘expert’, ‘I know, because I have one in my garden’. My explanation that there were about 300 different species of Cotoneaster, with many thousands of cultivars in a multitude of sizes and shapes, fell on deaf ears.
Indeed, this is also where correct understanding of plant naming is so critical – in particular if the plant has a ‘Cultivar’ at the end of the species name.
For example, Thuja occidentalis is an attractive conifer, native to North America and Canada and commonly known as the White Cedar. It makes a stunning specimen tree and can reach 20 metres or more in height. However, there are scores of cultivars (cultivated varieties) now grown – in a myriad of sizes and shapes, with foliage from blue-greens to golden yellow. Thuja occidentalis ‘Danica’ may struggle to reach 45cm (18”) in 10 years, whilst the cultivar ‘Columna’ will live up to its name – a narrow column of 10m, whilst spreading only 1.5m.
So how about Clematis. We all know what these look like – don’t we?
Scrambling climbers covered with abundant white or pink flowers in spring (Clematis montana types), or the later, large bloomed forms such as ‘Nelly Moser’ or ‘The President’ to name a couple of the many thousands of cultivars in production.
But how about Herbaceous Clematis? These are not climbers, but make a wonderful addition to the herbaceous border. Neat clumps of strong stems topped with heavenly scented clusters of tubular blue flowers which are magnets for bees and butterflies. Flowers start to appear by mid-summer and many are still flowering now – and I bet your neighbours do not have one!
We have a couple of good forms here at the nursery. Clematis ‘Cassandra’ has clusters of Oxford blue flowers and reaches just 60cm or so in height (around 2ft), whilst Clematis ‘Wyevale’ will reach 90-120cm (3 to 4ft).
I know that these are happy in our soil – a fairly heavy clay – as they are members of the Buttercup family, or Ranunculaceae. The family name is never written as part of the plant’s name, but is often worth finding out. We grow some superb specimens of the ‘weed’ creeping buttercup – a dead give-away that we are on a heavy, sometimes waterlogged soil! But knowing that, we can look out for other members of that family as they will thrive in the same conditions. So Aquilegia, Thalictrum, Hellebores, Delphinium are all doing well – as are the Nigella, or Love-in-a mist, a Hardy Annual, which self seeds prolifically. All genetically linked to a common ancestor dating back many thousands of years!
n Manea School of Gardening (RHS approved centre)
Plant sales on Saturdays, 10am -4pm, including all those mentioned above.