Crathes Garden blog #21: Blowing hot and cold

In the glasshouses the glorious scent of the Camellia tsaii caught my attention. This tender weeping camellia from China, Burma and Indochina was first introduced in Scotland by George Forrest in around 1917. It is being moved about as Joanna cleans and paints. Nearby is the Cestrum elegans ‘Rubrum’ from Mexico, also in full flower.

Joanna shows me the lily of the valley (Convallaria majalis) that she has been forcing for the show houses. This was a Victorian practice, devised to have the flowers for Christmas. A few plants were dug up from the garden in November, I think, and planted in pots. They were then left out in a safe place to catch a cold spell of weather – not a given these days, but such a spell obligingly arrived in late December. The pots were taken in just before Christmas and given some bottom heat. They were kept in the dark for about three weeks. As the lids were lifted and the light let in, we could see the emerging flower buds. Next week they will fill the show house with their delectable scent.

The cold snap before Christmas (it reached -11 in Torphins) was needed for the lily of the valley, but it damaged some of the tender plants. It did have the hidden advantage of keeping pests in control. As I write, the mild weather recedes and we have more seasonal weather as temperatures plummet again and snow falls.

One of my Christmas books was on ‘invasive aliens’ – a subject I have mentioned before (See A global perspective). [1] Spending much of my life living at the mouth of the Spey, I am well acquainted with some of the baddies: giant hogweed, Japanese knotweed and Indian balsam, all of which are spread by waterways and are almost impossible to control. Holidays on the west coast introduced me to the devastation wreaked by blanket Rhododendron ponticum, and I saw more of the rhododendron problem when I came to Crathes. Often these alien species are spread unwittingly by people. Gertrude Jekyll often planted giant hogweed, which does look an attractive architectural plant. Its presence in Moray is probably due to enthusiastic gardeners of grand estates. I have heard stories about Brodie Castle and Leith Hall in this context. However, giant hogweed can cause severe, permanent skin damage even when it is dead and dry.

I was guilty of sowing Indian balsam in my garden in the 1960s, when a friend gave me seed from what she called her ‘beauty plant. It grew happily and catapulted its seeds about abundantly. Apparently each plant can produce about 800 seeds. The bees love the flowers, but being an annual the plant dies back in the autumn. This leaves the river banks (that it has dominated throughout the summer) quite bare and exposed to winter erosion.

It is now a legal requirement that any Japanese knotweed is reported on the Home Report when selling a house. Its root system can penetrate tarmac, paving and even house foundations. Also in Speymouth I saw mink, which are so destructive when eating the eggs of terns that nest on the Spey shingle islands in the estuary. Grey squirrels did not get to Moray, but they were common around Crathes until the recent project to save the red squirrels.

The species I’ve mentioned above are aliens many of us know. However, Dan Eatherley’s book is full of horror stories of plants, animals and diseases that I had never heard of, many just waiting for the right opportunity. Some we have brought accidentally; some have been intentionally introduced with disastrous consequences, such as the rabbit in Australia. Some will come with global warming. Some will act benignly for a while and then turn rogue. Take the harlequin ladybird, introduced from Asia to the USA to control aphids. It did this for some time, keeping the Californian fruit orchards aphid-free, until it evolved into a wee monster that ate just about anything including caterpillars and other ladybirds, thus having a devastating effect on biodiversity. Active in England since 2003, it is now present in the south-east of Scotland. In mild areas it can proliferate by repeat life cycles, but the North East is a bit too cold as a rule.

I asked James about the aliens he feared might move into Crathes. He didn’t hesitate to name Phytophthora and the golden root mealybug, both of which he had known at Inverewe. The fungus Phytophthora ramorum has caused major problems all along the west coast in Scotland, attacking primarily rhododendrons and larches. The golden root mealybug (Chryseococcus arecae) comes from New Zealand and mainly devastates Meconopsis and Primula. It is not the cold that helps Crathes to avoid infestation of the mealybug, but the dry climate.

However, humans are probably the most invasive species. It’s who we are. We travel, explore, acquire, plant forests full of non-native trees and fill gardens with exotic plants. Crathes is living proof of this – and we wouldn’t want it any other way. But we do need to balance our creative urges with knowledge and regulations. And, judging by 2022, we need to prepare for changing conditions in the months ahead.

Updates

• The transition fund application has been successful and the diviner has recommended three possible sites for a borehole. Drilling took place in what was considered the most suitable site to the south of the bothy. At 100m depth, a steady but slow flow of water was found – enough to service at least the glasshouses and nursery, and maybe the bothy. Detailed assessment is now required.

• Work has begun on repairing damage to the Millpond caused by the November floods. The paths in that area are also being improved.

• There is a lot of work to do in the estate following the contractors’ removal of storm-damaged wood. Replacement planting will require a lot of thought.

[1] Invasive Aliens, Dan Eatherley, Harper Collins, 2019