This was Claire Tatler’s second visit to us. Previously she recounted her experiences ‘Gardening in Historic Places’ and a report of that presentation can be found on the website – Monday Night Musings. She continues to be in the employ of the mighty National Trust and is now Head Gardener at Wollerton Old Hall.
The Government paper on Climate Change Risk Assessment 2022, and that of the R.H.S. and the Meteorological Service, in their individual and separate research, all conclude Yes, our climate has already changed, and they will be monitoring closely for further long-term patterns of change.
Claire reassured us that although there was significant Doom and Gloom, her profession was working to find solutions to combat the effects of our changing weather patterns. 2023 has been declared the warmest year since records were started, and her talk this evening was about the effects on our gardens and how to go some way towards mitigating the worst of those effects.
Climate warming is not a new event and Claire took us back in history to the 750 -1450s when there were several climate warming events, but these were of volcanic origin. The effects then were global but beneficial with the increased warmth resulting in an increase in agriculture, new trade routes, introduction of new plants and even vineyards giving us wine production.
Now we have anthropogenic effects – non-global and more smaller area effects of human population, activities and industrial and agricultural practices – manifesting in mild winters; cold, wet summers; earlier leaf break; plants not developing their vernalisation – their dormancy period, needed to remain healthy. Insects and pollinators are showing a change in life cycles with the dreaded vine weevil now having four breeding cycles as opposed to just one.
Most cultivated plants in this country are not naturally native and adapted to our climate. Our native plants are better suited, although the group we now consider ‘native’ has developed over time.
- Native; – 10,000 years ago, before the last ice age
- Archeophytes – subsequent introduction
- Neophytes – more recently introduced, from places like the New World – and Asia and by the work of professional plant hunters.
Future proofing our gardens
This was the prime aim of Claire’s and her fellow garden experts. We must FUTURE-PROOF our gardens by growing a range of adaptable and dual-purpose plants, which will survive and grow on with little intervention from us, improving the soil conditions and adding biodiversity:
- those with long flowering period
- those which mitigate changing conditions; cornus and salix in wet ground to take the up the excess water
- those which develop long tap roots so they work to find the water
- those which will take care of themselves
- increase the gene pool by growing different and ‘foreign’ seeds, i.e. from outside your area, not overseas
- add to the biodiversity of your soil
- reduce chemical fertiliser use
- move away from anything affecting the make-up of your soil
- disturb the soil only if you must
- PROTECT and MULCH.
The big events of cool and cold, and hot and wet summers and warm, wet winters unfortunately do not perform to a seasonal expectation pattern. We have downpours one week, when the rain is falling on solid ground and therefore does not penetrate very far, and drought straight after – root rot one week and oxygen starvation to roots the next.
Testing
We must develop a strategy to take advantage of these big events of very hot or very wet weather to help our gardens survive. First, we must establish our soil type, and of course that may change from one side of your garden to another, and in tandem with that we test for pH levels and nutrients levels. There are simple kits available to give you the answers. Rain strips nitrogen out and also the precious small molecule nutrients of magnesium, iron, molybdenum and boron. Therefore, we must TEST, TEST, and continue to TEST through the seasons. The results will indicate your choice parameters for better suited plants which will put back some of the missing elements, e.g. beans for nitrogen required for leaf growth, potash for defence against poor conditions, phosphorus for root development.
Pests and diseases
On the plus side, Claire quoted a research project which indicated that some plants are evolving to protect themselves, and cited the Thyme which has developed increased strength production of phenolic compounds (scent) to deter attack by insects/predators. But negatively, the vine weevil now has four breeding cycles where there used to be only one. (See further list at end of article)
To summarise
- Test, and test again as the season progresses.
- Get to know your soil
- Choose plants to match your test results.
- Do not disturb the soil by digging unnecessarily. (Great idea!)
Claire’s lists of (not definitive) suggestions
Other pests and diseases
Knocking on our land boundaries:
- Mediterranean Fruit Fly
- Rose Jewel Beetle
- Phytopthera
- European Swallowtail
- Athelia Rolfsii
- Geranium bronze butterfly
Plants for dry conditions
- Salvia
- Geranium
- Achillea
- Stachys
Plants for wet conditions
- Alchemilla Mollis
- Filipendula
- Ajuga
- Lythrum
- Cornus
- Salix
- Hydrangea
- Iris
- Leycestaria
- Teucrum
- Dicentra
- Persicaria
The negative effects of using chemical fertilisers
- decreases organic matter
- hardens soil
- reduces natural pH
- increases pests
- causes soil crust
- stunts plant growth
- decreases soil diversity.
Answers to questions from the floor
Testing kits are readily available for nutrients as well as soil pH
- Blood, fish and bone is an OK fertiliser
- Chicken pellets are OK, but acidic, so do not use on acidic soils
- Seaweed feed excellent.
Sadly, it looks as though my usual practice of buying plants because I like the look of them is no longer sensible. I must become a plant chemist and choose more wisely if I want them to grow in my patch for any longer than half a season!