IT WAS not the year to promise a rose garden. The normally glorious blooms have been ranked among the worst performing plants of 2012 by curators of Scotland’s four Botanic Gardens.
Along with hardy perennials such as dahlias, marigolds and chrysanthemums, roses failed to thrive in gardens across Scotland after a year of extraordinary weather that brought a hurricane-force storm in January, a heatwave in March and one of the wettest summers on record for most parts, though the Western Isles and north-west Highlands faced drought.
The four curators compiled their list of winners and losers to find out which plants flourish in the extremely wet summers forecast to occur more regularly in future as a result of global warming.
While plants such as rhododendrons and hostas have revelled in the rainy conditions, many traditional favourites with large flowerheads have been unable to cope with the constant downpours. Experts fear some of the damage remains hidden.
David Knott, the curator of the Royal Botanic Garden Edinburgh, said: “The inclement weather has suited some plants and we have seen phenomenal growth. For others, flowering has been hindered. The full impact is difficult to determine immediately on, for example, the roots of trees which have been so saturated it could take seasons or even years to see the full picture.”
There was also more visible damage. On 3 January, the Botanics lost 34 trees, some up to 125 years old, during a hurricane-force storm, which gusted to 100mph. Glasshouses were also damaged with more than 600 panes shattered, exposing many tropical plants to the chill wind. By contrast, the garden also experienced its warmest March on record, as well as flooding in July.
Flowering plants also took a battering at the Logan Botanic Garden near Stranraer in Dumfries and Galloway. Curator Richard Baines said: “What happens with flowers like these is we plant them out and hope for a little rain to help them grow. But because we’ve had a steady stream the flowerbuds have not formed. If they have, the large flowers collect water and quickly rot away.”
Some plants had been in their element, however, said Baines. “Plants like gingers and rhododendrons, which originate in countries like China and Burma, would normally be growing in damp and muggy conditions quite similar to what we’ve experienced this summer. They get a lot of precipitation during the growing season. These sorts of plants have put on a massive amount of growth in 2012 compared to normal years.”
Gardeners everywhere struggled to cope with the unusual weather, he added. “It’s been an extraordinary year. I can’t remember such high temperatures as we had in March, in fact it was so hot some days we were having to keep plants cool in the greenhouse. Then in May we had frost for the first time in 20 years, and then in the summer we had such wet conditions we actually had to close the gardens on a couple of occasions.”
Meanwhile, Dawyck Botanic Garden in the Borders lost 13 trees in the January storm, the most notable being a 50-metre Noble fir believed to be at least 100 years old. Curator Graham Stewart said it had been a big loss. “Losing a notable tree can be like losing an old friend,” he said. “They are impossible to replace. It was sad for everyone to see. However, we have to be philosophical about it, and look upon loss as opportunity for replanting.”
Some plants at Dawyck have thrived in the bad weather. The constant rain has given a boost to plants such as hostas, irises, ferns and ligularia, which like wet conditions.
“Anything that comes from a wetter habitat – whether that be a stream side, a lochside or a riverside, has thrived,” said Knott. “Hostas and ligularias are moisture-loving plants and they’ve done exceptionally well, even on the allegedly drier east coast.”
Fruit growers also had a miserable season with the heavy rains in spring washing away the blossom required for a good crop. Pollinators such as bees, butterflies and hoverflies were also unable to thrive in the heavy rains.
The results of the analysis will influence future plantings. Suzanne Martin, the Botanics’ climate officer with ClimateXChange, the Scottish Government’s centre of expertise, said: “We need to start considering how the climate is predicted to change and to understand the types of impact that may have on our botanic gardens. The experience of more extreme events such as heavy rainfall and storms is broadly consistent with climate-change predictions while providing a powerful example of a degree of uncertainty to which we must adapt.”
Scottish gardeners will continue to adapt to the changes in climate, Knott said. “Gardeners are normally fairly pragmatic individuals. If something doesn’t do well for a couple of years, they’ll change what they’re doing.”