WANDERING PLANTS

WANDERING PLANTS

The garden continues to throw up surprises. The other day an elegant mauve spike of an Autumn Crocus appeared at the base of the Japanese Cherry. I bought a pack of ten corms of this lovely crocus about twenty years ago and planted them at the foot of a Eucalyptus. They never really thrived, and they dwindled over the next few years, disappearing and forgotten 'till now! The cherry is some thirteen yards away  - I paced it - from that original planting.  I assume the culprit was a mouse, but it was a long time gap till its reappearance.

Autumn Crocus October 2020

 

 

Cyclamen hederifolium October 2020

Earlier, I had to keep a path blocked off because the Cyclamens I’d put in at the side of the path have encroached and  are in danger of being trampled. And meanwhile, a pure white one (the rest are pink) has come up among the ferns a couple of yards away. I understand that ants will move cyclamen seed, no doubt intending them for their nest, but dropping the odd one on the way.

 Ant watching. Over the years I have spent many hours on my knees in many countries, watching trails of ants of all kinds laboriously carrying trophies back to their nest. They wear visible tracks in the soil, radiating away from the nest hole in the ground. Often this hole is at the bottom of a crater, surrounded by a bank sometimes a couple of inches high, of soil or sand particles and other debris brought out of the nest. The ants vary; the lazy ones just drop their load at the entrance hole while the more civic-minded struggle to the top of the bank before discarding the rubbish. Rather mean, I have on one occasion, partly blocked their entrance with a bit of dry grass about an inch across. It was ignored and by-passed by the outgoing ants for some time before one  took the initiative and dragged it clear.

The incoming workers are mostly indefatigable in the face of obstacles which would defeat a human, struggling usually single-handed with loads often far larger, longer or heavier than themselves, attempting to scramble over obstructions far greater than themselves. They rarely seem to give up the struggle and abandon the load. Sometimes others will come to help but this often seems to be uncoordinated, with ants pushing and pulling in different directions before giving up and going to find their own cargo. The loads are usually plant seeds; sometimes a caterpillar or other insect and some do love cake crumbs donated by the audience! As the trails divide and branch as they get further from the nest it’s impossible to see how far the foragers will range but it is many yards.

 

 Busy highways. Ant trails to their nest in Western Australia. These tracks in the sand were about 3inches wide.

One kind of Australian ant makes a volcano-shaped entrance to their nest. We watched another sort, with their entrance hole flat on the ground, being flooded one day in the south of Australia. The ants swarmed out and formed rafts as they clung to each other, and floated away on the water. They appeared to have abandoned their brood still underground.

 

 We blame the squirrels for burying Hazel nuts before we get to them; our only share in the harvest is umpteen seedlings coming up all over the garden the following year. And Oaks. I read in an Oliver Rackham book once that Oaks rarely come up as seedlings within British oak woodland, but instead come up in the meadowland beyond the wood, no doubt buried by Jays and Squirrels. I remember though, that we have often seen plenty of oak seedlings coming up within oak woods in France! Some other factor must be in play.

Two stories about the spread of plants have passed into botanical folk-lore. The first is about Oxford Ragwort, a plant found growing on the rubbly lava slopes of Mt Etna and brought back to the Oxford Botanical Garden in the late 1700s. It was said to have ‘got on the train at Oxford and travelled through the country, getting off at the stations.’ Trains  came much later and I suppose its parachute seeds could have got whisked along in the draught made by passing trains. It can be seen in stony waste ground such as railway and road construction ballast. Shorter, more branched than Common Ragwort, it contains the same  toxic alkaloids as Common Ragwort and can be poisonous to stock if eaten in significant quantity.

Another story is that seeds of the promiscuous American Willowherb (Epilobium ciliatum) came to this country in the wheel-treads of American military lorries during the second world war. It has subsequently hybridized with several of our native Willowherbs , making a slightly tricky genus of rather  ‘weedy’ wildflowers  even more difficult to pin down to species-level. This story seems to be more romantic than factual as this plant was first identified in Leicester in 1894!

American Willowherb

Many plants have been brought into this country from all over the world by plant collectors, but mainly from the Far East and America. Most of them are well-behaved, tolerate or even enjoy our climate and enrich the huge variety of our ornamental gardens. Notable exceptions include Japanese Knotweed, Rhododendron ponticum, Himalayan Balsam and several pondweeds. These plants originally thought to enhance our gardens have escaped and through their aggressive and invasive habits threaten to overwhelm our natives.

Young Japanese Knotweed coming up in the spring.

Later in the year it will make impenetrable thickets with a thick mat of roots, smothering everything. The smallest fragment of root will survive to make more invasive growth.

It was introduced from the far east as an ornamental shrubbery plant with attractive flowers.

Another handsome but now unwelcome introduction, Himalayan Balsam. When ripe, the seed capsules pop open and catapault the seeds many yards. They are spongy and will float in water, spreading the plant far and wide along streams and river systems. It is an annual but will make very big robust growth in the one season.

Plants will spread between continents by other means. The struggling early settlers in Australia, faced with their starving cattle, imported hay from South Africa. This brought in the seeds of various ‘weeds’ such as Hottentot Fig or Pig Face which will make an impenetrable mat, suppressing less vigorous plants especially on the coast.

It seemed a good idea at the time when European Gorse and Blackberries were taken to Australia, the Gorse as a hedging plant and Blackberries for their berries, a taste of ‘home’. They rapidly became pests especially in the southern states of Australia and rigorous measures are taken in an effort to control them now. 

Australian wattles (Acacia species) are trees which will flourish in arid conditions; introduced from Australia to the Cape Province in South Africa for their timber and forage, their success has become overwhelming and they are now subject to strenuous efforts to eradicate them. 

Similarly apparently innocent plants were introduced from Britain to America in the 1800s: Garlic Mustard or Jack-by-the-Hedge was seen to be useful as a culinary and medicinal plant. A few years ago a friend sent me a cutting from a newspaper in Des Moines in Iowa, appealing for volunteers to help pull up Garlic Mustard from their public parks. It is now described as a noxious weed there. Similarly the handsome Purple Loosestrife, originally introduced as an ornamental plant, now clogs the waterways and is another certifiable alien!

We have the Romans to blame for bringing in that pernicious Ground Elder. They ate it. I’ve tried. It’s like eating linen!

The last ice age which ended some 12000 years ago was a great factor in the impoverishment of our native flora. Only plants growing in small pockets of land left in the grip of the Arctic climate survived. These true natives include Scots Pine.

As the ice melted and we were gradually cut off from the rest of Europe the natural re-colonization by plants moving northwards was arrested and led to a comparatively sparse flora our side of the Channel. It was an open invitation to new-comers, particularly arable weeds which came in with the early farmers whose culture diffused across Europe from the Middle East. Many of our plants which we now accept as natives, in fact date from after the last Ice Age. They are known as  Archaeophytes . Plants which were brought to this country after 1500 are called Neophytes.

 By far the most common methods of plant movements are due to strategies adopted by the plants themselves in order to spread .

 

The hooked seeds of Burdock will be carried on animals' fur.

 

More hooks, this time on  Cleavers or Sweethearts. Remember when the boys at  junior school threw them at you? If they stuck, you were their sweetheart! Another name is Goosegrass. Geese love the seeds and will neatly nibble them off the stem.

 

Many of the Daisy family have parachutes on their seeds. Children pretended to tell the time by counting the number of puffs it took to blow away all the seeds of the 'dandelion clock'. In the late spring the air can be full of the silky drifts of Willow seeds blowing away on the wind.

 Sycamore 'propellers'. Many trees have winged seeds to disperse them.

Hornbeam seed.

Lime seed and wing.

The wings or samaras on Wych Elm in spring.

Ash Keys. Will they become an unfamiliar sight as Ash Die-back takes a grip of parts of the countryside?

 

 Even the smaller seeds of Birch and pines have wings on the seeds when they are eventually released by the ripening and opening of catkins and cones.

 Seeds are born within edible berries, eaten, rendered fit for germination within the animal’s gut and then passed out in droppings. Mistletoe seeds have a sticky covering which birds will wipe off their beaks by rubbing them on the bark of trees, which sometimes has the effect of planting the seed in crevices.

There is a very heavy crop of berries this year. Hawthorn is popular with newly-arriving Redwings and Fieldfares from Scandinavia.

 

 

Ropes of poisonous Black Bryony berries drape the hedges in the autumn.

The fleshy pink covering of Yew berries. These colourful berries are also very popular with Redwings.All parts of the Yew are poisonous except for the fleshy 'aril' surrounding the seed.

The last of the berries. Ivy berries don't ripen till after Christmas, a welcome food for birds in the lean and hungry time of the year.