At this time of year I start the slow and steady process of pruning all my roses. I do it in bite-sized chunks, and it always takes me a couple of weeks to get round all of our 150-odd shrub rose bushes.
I like doing it, but I like pruning some more than others. This is partly down to their inclination to be less tangled or less vigorous but mostly because they are less thorny.
Some roses, such as Scharlachglut or Gipsy Boy, have wickedly loose, arching stems armed with thorns like broad daggers, and they flick and flop.
British gardening expert Monty Don has revealed now is the time to start the slow and steady process of pruning roses
I have often found myself ensnared in a tangle of rose, pinioned by thorns to my scalp, cheek and hands as I have to slowly, painfully, bloodily, free myself. Who said gardening was a gentle pastime?
Thorns, prickles and spines have evolved from other parts of plants to respond to specific circumstances.
So a thorn is a stem or miniature branch, emerging from the woody core of the plant, that often has no leaves, is exceptionally rigid and has very limited growth.
A spine, however, is a modified leaf. Thus cacti spines are leaves that have evolved to cope with drought by having a small surface area and a hard surface that loses water very slowly.
Finally, prickles, like those on a raspberry cane, are actually outgrowths of bark.
He also explored how thorns, prickles and spines have evolved from other parts of plants to respond to specific circumstances (berry-laden cockspur thorn pictured)
Ask Monty
Peach trees produce fruit on growth made the previous summer
Q How should I prune a fan-trained peach tree that is attached to a garage wall?
Margaret Thompson, Lutterworth, Leics
A Peach trees produce fruit on growth made the previous summer, so prune by cutting old wood back to a vigorous new shoot and tie this in to grow and replace the old section.
Also, remove crowded growth or shoots growing away from or into the wall. Do this in mid-summer, immediately after harvesting any fruit.
Worm casts are a good sign that your soil is healthy
Q My lawn is littered with worm casts. How can I cure the problem?
Deanna Elliott, Reading, Berkshire
A Worm casts are a good sign that your soil is healthy.
The best way to deal with them is simply to brush them – when dry enough – back into the grass.
Alstroemerias grown indoors need generous pots
Q I have a pot of alstroemerias and a container of penstemons. When should I cut both back, and by how much?
Hilda Micklewright, Charlwood, Surrey
A Alstroemerias grown indoors – a greenhouse or conservatory is ideal – need generous 5ltr pots filled with good peat-free compost.
Water well and feed with liquid seaweed once a week.
Do not cut them but pull them from the root. Penstemons should be left uncut but supported until April, then cut back very hard. New shoots will soon appear.
One obvious way to differentiate a prickle from a thorn is that prickles, which grow from the surface of the bark or outer layer of a stem, can usually be broken off whereas a thorn, which grows from the core wood inside its parent stem, might snap but is unlikely to detach.
We call roses thorny but they do not in fact have thorns but prickles – botanically at least – since they grow not from the stem itself but its surface.
But call them prickle or thorn, the range of size, shape and density is huge – from the incredible blood red shark’s fins of Rosa sericea pteracantha, which is grown entirely for the beauty of its thorns, to the bristles that run up the stems of R. nitida and R. rugosa.
The most common thorn in the British countryside is Crataegus, the hawthorn, which makes up thousands of miles of hedging around fields and is woefully underused as a garden hedge.
It is cheap, grows almost anywhere, will take any amount of hard cutting yet holds a crisp outline, is wonderful for wildlife and makes a good thorny barrier.
The most dramatic hawthorn spikes are produced by the cockspur thorn, Crataegus crus-galli – up to 10cm long and curved like a cockerel’s spur.
But even these are no match for the thorns of Prunus spinosa, blackthorn, which are wickedly sharp.
It’s not a plant I’d recommend for any but the biggest garden, and then only as a defensive boundary hedge.
This is because its spines are truly dangerous, being not just big and sharp but also very brittle, so they can easily break off under the skin and cause infection.
There are ‘good’ thorns, though, that I grow as border plants. Rubus cockburnianus ‘Goldenvale’ is crusted with prickles up its pinky-red stems, which are dusted liberally with a white bloom.
These are then covered with lime-green foliage in spring and summer.
However it has to be kept under control. Whenever the arching stems touch the soil they put down roots, and soon it becomes an impenetrable thicket.
So I forgo the summer display and cut the whole thing to the ground each spring, which clears the border and encourages vibrant new growth that will have the best colouring the next winter.
MONTY’S PLANT OF THE WEEK
LICHENS
Every so often, people ask me how to get rid of the ‘problem’ of lichen – half-fungus, half-alga organisms – on their fruit trees or shrubs.
But to do this would be a mistake and, at worst, eco-vandalism – the fact that you have lichen is a sure sign that the air is clean.
Also, they cannot harm their host, whether of plant material or stone.
So if you have lichens growing in your garden feel privileged, relish them as a sign of health and celebrate their subtle beauty as they encrust the branches of trees with their delicate but rich colours.
Lichens growing in your garden are a sign of health and celebrate them for their beauty as they encrust the branches of trees with their delicate but rich colours
THIS WEEK’S JOB
PRUNE HELLEBORES
Cut off old leaves now so you can see the flowers as they develop. Letting light and air in also helps prevent the disease hellebore black death.
This shows as a chocolate blotching on the leaves, which then go yellow and die. Burn affected leaves or take to the refuse tip.
Pruning hellebores is important as letting light and air in also helps prevent the disease hellebore black death