Week 35
There are times when my renatured land looks messy, and times when it appears fantastic. Right now, messy is the order of the day. As autumn fast approaches, and flowers begin to fade, for those who may judge land more by appearance than function, I sense them becoming restless. I must work harder at explaining my way.
For several weeks I have been waiting for the pinky-purple devil’s-bit scabious[i],[ii] to appear, as I had plenty last year, but none right now. It has set me thinking why a plant flowers one year but not the next, especially when I am using neither chemicals nor fossil fuels. Devil’s-bit scabious prefers damp soils and being out of full sun, which is precisely the environment I offer. By rights I should now be seeing a technicolour display of this pinky-purple perennial, but sadly that is not the case.
What is a perennial? It means a flower that lasts longer than two years. In contrast there is an annual, which is a plant that germinates, blooms, sets seed and dies all in one year. It does not mean the plant will disappear forever after its first year. It does mean that any flowers in the second year come from the seeds of that first annual. Each year produces seeds for the next. Biennial plants have a life cycle of two years, germinating and growing one year, blooming and dying the next[iii]. Examples of perennials on my land include basil[iv], common sage[v], yarrow[vi], chives[vii], lavender[viii], and phlox[ix],[x]. Annuals might be marigolds[xi] and geraniums[xii], while biennials include common mullein[xiii] and foxglove[xiv].
Why a flower appears one year but not the next can be thanks to many reasons. Failure to flower is just one symptom of an unhappy plant[xv].
For my devil's-bit scabious, I decided to pretend I was Sherlock Holmes and see if I could establish why it has not flowered. Despite the plant’s robust nature, there were several reasons that might explain its failure. These included:
1. Soil and Nutrients: Like all plants, the devil's-bit scabious has specific soil requirements. It thrives best in moist, well-draining soils that are slightly acidic to neutral. If the soil is too rich, particularly in nitrogen, the plant may produce lush foliage at the expense of blooms. Conversely, nutrient-depleted soils may not provide the plant with the necessary ingredients to flower. There was some limited nearby flooding earlier in the year, which might have drained nutrients, but I suspect this would have affected other flowers as well, which it did not. This year there has been a truly impressive floral display, with scabious being the only one missing, so I sense soil quality is unlikely to have been the issue.
2. Water: Although devil's-bit scabious enjoys moist conditions, it does not fare well in waterlogged soils. Over-watering, or planting in areas with poor drainage, can stress the plant and reduce its flowering potential. Conversely, long dry spells or under-watering can also deter flower production. The Lake District experienced prolonged hot weather and zero rain in June, which is the month I would expect to see scabious, and certainly no later than July[xvi]. Water, actually lack of it, may thus play a part in my missing scabious.
3. Insufficient Light: While scabious is versatile in terms of sunlight and can tolerate partial shade, it requires a good amount of sunlight to flower profusely, albeit not full sun. That is precisely what my land offers.
4. Incorrect Pruning: While the devil's-bit scabious does not require regular pruning, it can benefit from occasional deadheading. I did not deadhead the scabious last year, as I am not a supporter of deadheading anyway, but even without deadheading I would expect to see at least one flower. Last year there were plenty. This year there are none. Consequently, incorrect pruning is unlikely to be the problem.
5. Pests and Diseases: Devil's-bit scabious is theoretically susceptible to pests and diseases but is generally resistant, although it can sometimes be affected by powdery mildew[xvii]. This is a fungal condition and one of the easier plant diseases to identify. Infected plants show white powdery spots on leaves and stem. Powdery mildew affects many different plants, not just scabious, and I see no evidence of it anywhere on my land. I can thus exclude powdery mildew as a cause of non-flowering.
6. Maturity: Young plants, or those recently divided, might not flower immediately. They often need a season or two to establish themselves and gather enough strength to flower. My scabious has never been pruned, nor divided, and is already well established. Plant maturity thus cannot be the reason why my scabious has not flowered.
7. Climate and Weather: Extreme weather such as late frosts, excessively hot and dry periods, or sudden cold snaps can affect flowering. These adverse conditions can either damage budding flowers or stress the plant, making it prioritise survival over reproduction. There was a late frost on one occasion this year, and there was also June’s drought. Climate and weather may thus be the problem.
8. Natural Cycles: Not all plants flower annually. Some have periods when they invest more in root growth and other vegetative functions than in flowering. My scabious was formerly widespread and scattered over different parts of my land. For there to be no scabious anywhere does not fit with a natural cyclical pattern, where you might expect some to appear in one place, others somewhere different, and others not at all. I thus exclude natural cycles on this occasion.
9. Propagation Methods: How a plant is propagated can sometimes influence its initial flowering patterns. For instance, plants grown from seed might take longer to flower than those propagated from divisions or cuttings. Being a renaturer, plant propagation is not something I do, so would not apply to my scabious.
10. Competition: Plants, like all living organisms, compete for resources. My devil's-bit scabious is certainly surrounded by more aggressive and faster-growing plants that might try to discourage it. However, because the scabious is in different locations on my land, I would have thought at least one specimen would have featured somewhere if other plants were waging territorial war. To me, therefore, competition from other plants is an unlikely cause of scabious failure.
My conclusion? Surely it is obvious. This year my devil’s-bit scabious has not flowered because the weather has not allowed it. It was either the late frost, or the dry June, that has made my land scabious-free this year. This is likely down to the environment, where 85% of the world’s population is already affected by human-driven climate change[xviii]. Devil’s-bit scabious failing to flower on my land is a tiny problem compared with the struggles being faced by so many. Yet it reflects the bigger picture. Climate is the issue, so let us not forget that.
However beautiful Lakeland may be, and there is no doubting its attraction to many, its topsoil is generally thin. If I can dig a hole in my land deeper than 20cms before I strike bedrock[xix], I am doing well. It is why the drainage of water is a problem, why so much of the vegetation on my land prefers moisture, and why, when I see news headlines from around our burning planet, I realise that Lakeland is a lucky place to practise renaturing. Yet water means I must think about drainage.
When I first arrived in Lakeland, and because my land is towards the bottom of a hill, I could see surface puddling of water after many of the rainstorms that affected my area. Lakeland receives around 200 days of rain each year[xx] and some parts of the area flood frequently. The experts classify floods into different categories - flash, coastal, urban, river (fluvial) or ponding (pluvial)[xxi].
Pluvial flooding is my worry, although nothing has ever come close to my house. It is why I am perplexed when I see folk felling trees to make space for more building. Trees absorb huge amounts of water[xxii] over a year, so the moment a tree is felled, the chances of pluvial flooding increase significantly. I am even more perplexed that planners agree a tree can be felled - they should know better - and is why I spend much time pondering drainage. To install drainage may simply require the digging of an open ditch, or a French ditch[xxiii] if an open ditch is unsuitable.
A French ditch is constructed by filling a ditch with coarse gravel topped with permeable membranes or upturned turf to keep soil from entering the gravel. The ditch is then covered with topsoil[xxiv]. French ditches may well be used in France but their true origin is one Henry French (1813-1885), a well-respected American agriculturalist, lawyer, and politician. He was also a prolific writer, although wrote only one book, in which he described his drain[xxv].
There are also soakaways[xxvi], but the likeliest drain used by many is the burying of porous pipes laid in trenches. This is skilled and heavy work and a technique I thought might be suited to a boggy area of my land. I even had plans drawn up to do this. It was then that I noticed something remarkable. As my renatured grass grew longer, so the bogginess vanished. Puddling went, surface flooding went, and that was despite tree-felling all around. It set me thinking.
The type of grass can also be important[xxvii] and efforts have been made to modify grass so that it slows down water better. For example, the commonly used rye grass is 51% less effective at controlling water run-off than a new species developed called Festulolium[xxviii]. In addition, grass roots can be extremely long, between six inches and two feet[xxix], and the longer the blade, the longer the root. For a stripy lawn, where the grass is short, it has been suggested that the grass can only absorb 2 inches of water per hour while a forest can handle 14 inches in the same time frame[xxx]. When the grass is longer, this may be different.
Root size does not always mean that larger is better when it comes to water absorption. Large roots, as may form part of a mature tree, do not always absorb water, while fine roots may not absorb water from a dry soil. Different roots behave differently. Most root biomass is found in shallow soils, with half of active grass roots being more active in the top 12cms and half of active tree roots more active in the top 21cms[xxxi]. It is rare for my land to have topsoil as thick as 20cms and I only see that in a few places. Thanks to the shallow topsoil all around me, it may just be that grass roots are as helpful as tree roots for absorbing water.
The question I put to myself was thus obvious. Would one way of reducing pluvial flooding be simply to leave grass long[xxxii]?
Although I felt I had an original idea, I had not. There is plenty of evidence to suggest that longer grass helps reduce pluvial flooding. Here are a few reasons why:
1. Increased Water Absorption: Longer grass means deeper roots and a denser canopy, both of which can absorb or retain more rainwater. This reduces the amount of water that runs off a surface and might otherwise result in pluvial flooding. In addition, the roots of tall grasses and native plants can create channels that help water penetrate the soil more effectively.
2. Improved Soil Structure: Longer grass helps improve soil structure over time. Grass roots bind the soil particles together, which promotes water retention and reduces surface runoff.
3. Reduced Erosion: Tall grasses and vegetation slow down the movement of water over the soil surface. This minimises soil erosion and the transportation of sediment into storm drains, which can lead to clogging and thereby exacerbate flooding.
4. Natural Filtration: Longer grass and vegetation act as natural filters, trapping pollutants and impurities present in rainwater. This not only reduces the pollution of water bodies like nearby Windermere, but also prevents the build-up of debris in drainage systems, which can contribute to flooding.
5. Research: Numerous research projects have demonstrated the benefits of long grass management. For example, the Wildfowl & Wetlands Trust[xxxiii] found that taller grasses in wetland areas helped slow down water flow and reduce flooding downstream. Similar research has been conducted in urban and suburban settings, showing the positive effects of natural landscaping on the reduction of flood risk. The Journal of Hydrology has published research to show that grass is particularly effective at reducing the overland flow of water. The above-ground element of grass can reduce this by 64%, while the roots can lessen soil erosion by up to 84%[xxxiv].
6. Official Recommendations: Many organisations recommend long grass management as a flood prevention strategy[xxxv],[xxxvi]. In addition, they frequently emphasise the importance of incorporating native plants and reducing impermeable surfaces, such as concrete or asphalt, to improve water absorption. Critically, not everything is equal when it comes to water absorption. Some plants do it well, others not so well.
On my land good water absorbers include Lily of the Valley[xxxvii], flag iris[xxxviii], and ferns[xxxix]. Ferns are especially good, as not only do they have a dense root system, but their foliage is also said to be water-absorbing[xl].
Unrelated to its ability to absorb water, I am still waiting for my first fern flower if such exists. Slavic folklore says that anyone who sees a fern flower will be happy and rich for the rest of their life. Who would not want that? The flower is supposed to bloom on the eve of the summer solstice and can also allow an understanding of animal speech[xli]. I must clearly keep hunting for a fern flower, as its properties sound remarkable. I still find it hard to understand sheep, which is a language you should speak in Lakeland. Maybe a fern flower can help me.
So, I have a problem. In addition to seeking lifelong happiness and wealth, which somehow seem to elude me, I will soon have to cut my long, renatured grass. A scythe is how I do it. Yet when I shorten the grass, I may increase the chance of pluvial flooding. It sounds to be tough luck. Flooding or no flooding, I will soon be obliged to act.
***
Acknowledgement
Take it from me - none of this would be possible without the help of RSG Horticulture. Rufus, who runs it, has far more energy than me and is full of ideas and skills. Do contact him through https://www.rsghorticulture.com.
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#GrassAgainstFloods #RenaturedLandscapes #ClimateReflections #GardenDetective #NatureDetective #RewildingLakeland
References [i] See week 1 entry [ii] The Wildlife Trusts. Devil’s-bit scabious (Succisa pratensis). Devil's-bit scabious gets its Latin name - 'Scabere', meaning to scratch - from its traditional use as a treatment for skin conditions, such as scabies and the sores of bubonic plague. Its common name arises from the fact that its roots look truncated, as if bitten off, legend has it, by the Devil. Found in damp meadows and marshes, and along woodland rides and riverbanks. It is in bloom between July and October, its pincushion-like flower heads attracting a wide variety of bees and insects. It is also the foodplant for the declining Marsh fritillary butterfly. See https://www.wildlifetrusts.org/wildlife-explorer/wildflowers/devils-bit-scabious. Accessed 24 August 2023. [iii] The Sunday Gardener. What is the difference between Annual, Perennial, and Biennial Plants? See https://www.sundaygardener.co.uk/what-is-an-annual-perennial-biennial-plant.html#:~:text=Annual%20plants%20germinate%2C%20bloom%2C%20set,and%20flowers%20for%20many%20years. Accessed 24 August 2023. [iv] Basil (Ocimum basilicum). The name "basil" comes from the Latin basilius, and the Greek βασιλικόν φυτόν (basilikón phytón), meaning "royal/kingly plant", possibly because the plant was believed to have been used in production of royal perfumes. Basil is likewise sometimes referred to in French as "l'herbe royale" ('the royal herb'). The Latin name has been confused with basilisk, as it was supposed to be an antidote to the basilisk's venom. See https://en.wikipedia.org/wiki/Basil. A basilisk is a legendary reptile, reputed to be a serpent king, who causes death to those who look into its eyes. See https://en.wikipedia.org/wiki/Basilisk. Accessed 25 August 2023. [v] Sage (Salvia officinalis). Sage has slightly stimulating properties; tea brewed from its leaves has been used as a tonic for centuries. In medieval Europe, sage was thought to strengthen the memory and promote wisdom. See https://www.britannica.com/plant/sage-plant. Accessed 25 August 2023. [vi] See week 30 entry. [vii] Chive. Allium schoenoprasum. Small perennial plant of the amaryllis family (Amaryllidaceae), related to the onion. Chives are grown as ornamentals for their attractive flowers and as a potherb for their flavourful leaves. The leaves can be used fresh or dried and are a common seasoning for eggs, soups, salads, and vegetables. See https://www.britannica.com/plant/chive. Accessed 25 August 2023. [viii] See week 31 entry. [ix] Cuttle S. Phlox. See https://www.rhs.org.uk/plants/phlox. Accessed 24 August 2023. [x] Wikipedia. Phlox. The name is derived from the Ancient Greek word φλόξ "flame". Phlox are valued in the garden for their ability to attract butterflies and can be propagated from stem cuttings. See https://en.wikipedia.org/wiki/Phlox. Accessed 23 August 2023. [xi] See weeks 30 & 32 entries. [xii] Mattern JL, Robertson T. The 18 Best Annual Flowers and Plants to Bring the 'Wow' Factor. 14 March 2023. See https://www.countryliving.com/gardening/garden-ideas/g19564804/best-annual-flowers/. Accessed 24 August 2023. [xiii] Verbascum thapsus. It is a hairy biennial plant that can grow to 2 m tall or more. Although long used in herbal medicine, no drugs are manufactured from its components. Dioscorides first recommended the plant 2000 years ago, considering it useful as a folk medicine for pulmonary diseases. Leaves were smoked to attempt to treat lung ailments, a tradition that in America was rapidly transmitted to Native American peoples. The Zuni people, however, use the plant in poultices of powdered root applied to sores, rashes, and skin infections. An infusion of the root is also used to treat athlete's foot. All preparations meant to be drunk have to be finely filtered to eliminate the irritating hairs. See https://en.wikipedia.org/wiki/Verbascum_thapsus. Accessed 25 August 2023. [xiv] RHS. 10 of the best...biennials. See https://www.rhs.org.uk/plants/articles/graham-rice/perennials-and-bulbs/10-agm-biennials. Accessed 24 August 2023. [xv] RHS. Non-flowering woody plants. See https://www.rhs.org.uk/problems/non-flowering-woody-plants. Accessed 24 August 2023. [xvi] Devil’s-bit scabious. See https://www.wildlifetrusts.org/wildlife-explorer/wildflowers/devils-bit-scabious#:~:text=The%20rounded%20and%20nodding%2C%20purple,variety%20of%20bees%20and%20insects. Accessed 24 August 2023. [xvii] Powdery mildews. See https://www.rhs.org.uk/disease/powdery-mildews. Accessed 24 August 2023. [xviii] Barna M. Climate change impacts almost entire global population. 11 December 2021. See http://www.publichealthnewswire.org/?p=climate-update-2021#:~:text=As%20the%20world%27s%20climate%20continues,in%20Nature%20Climate%20Change%20finds. Accessed 24 August 2023. [xix] Wikipedia. Bedrock. See https://en.wikipedia.org/wiki/Bedrock. Accessed 23 August 2023. [xx] See https://www.lakedistrictweatherline.co.uk. Accessed 23 August 2023. [xxi] Floodsite. Flood types. See https://www.floodsite.net/juniorfloodsite/html/en/student/thingstoknow/hydrology/floodtypes.html. Accessed 23 August 2023. [xxii] See week 14 entry. [xxiii] Wikipedia. French drain. See https://en.wikipedia.org/wiki/French_drain. Accessed 23 August 2023. [xxiv] Royal Horticultural Society. Drainage: installing. See https://www.rhs.org.uk/garden-design/installing-drainage. Accessed 23 August 2023. [xxv] Henry F. French. Farm Drainage; the Principles, Processes, and Effects of Draining Land. Publ. Orange Judd & Company, New York. 1859. See https://archive.org/details/farmdrainageprin00frenrich/page/n5/mode/2up?view=theater. Accessed 23 August 2023. [xxvi] See week 14 entry. [xxvii] Grabar H. When It Comes to Flood Prevention, Not All Grass Is Created Equal. See https://www.bloomberg.com/news/articles/2013-04-25/when-it-comes-to-flood-prevention-not-all-grass-is-created-equal. Accessed 23 August 2023. [xxviii] Cotswold Grass Seeds. Festulolium (Hybrid). See https://www.cotswoldseeds.com/species/131/festulolium-hybrid. Accessed 23 August 2023. [xxix] McCullah S. Grass 101: How Deep Do Grass Roots Grow? 11 May 2022. See https://www.angi.com/articles/grass-roots.htm#. Accessed 23 August 2023. [xxx] PennState College of Agricultural Sciences. For Water Quality: Creating Woods Instead of Lawns. 7 January 2020. See https://ecosystems.psu.edu/research/centers/private-forests/news/for-water-quality-creating-woods-instead-of-lawns#:~:text=Your%20lawn%2C%20because%20of%20grass,in%20the%20same%20time%20frame. Accessed 23 August 2023. [xxxi] Mazzacavallo MG, Kulmatiski A. Modelling Water Uptake Provides a New Perspective on Grass and Tree Coexistence. PLoS ONE 2015;10(12): e0144300. https://doi.org/10.1371/journal.pone.0144300 [xxxii] Zhu A. Less mowing on more public property could help reduce flooding, city hopes. See https://www.news-leader.com/story/news/local/ozarks/2017/05/16/less-mowing-more-public-property-could-help-reduce-flooding-city-hopes/101758664/. Accessed 23 August 2023. [xxxiii] See https://www.wwt.org.uk/about-us. Accessed 24 August 2023. [xxxiv] Li C, Pan C. The relative importance of different grass components in controlling runoff and erosion on a hillslope under simulated rainfall. Journal of hydrology. 2018 Mar 1;558:90-103. [xxxv] Rewilding Britain. Rewilding and flood risk management. See https://www.rewildingbritain.org.uk/why-rewild/benefits-of-rewilding/rewilding-and-flood-risk-management. Accessed 25 August 2023. [xxxvi] Rewilding Britain. Reduce flood-risk through rewilding, says new report from Rewilding Britain. 21 September 2016. See https://theecologist.org/2016/sep/21/reduce-flood-risk-through-rewilding-says-new-report-rewilding-britain. Accessed 25 August 2023. [xxxvii] See week 16 entry. [xxxviii] See week 23 entry. [xxxix] Fern. The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They first appeared in the fossil record about 360 million years ago. Fern species live in a wide variety of habitats, from remote mountain elevations, to dry desert rock faces, bodies of water or open fields. Ferns in general may be thought of as largely being specialists in marginal habitats, often succeeding in places where various environmental factors limit the success of flowering plants. They are . are the national emblem of New Zealand. See https://en.wikipedia.org/wiki/Fern. Accessed 23 August 2023. [xl] Evergreen Seeds. 23 Plants That Soak Up Water and Thrive in Wet Soils. See https://www.evergreenseeds.com/plants-that-soak-up-water/. Accessed 23 August 2023. [xli] Fern flower. See https://en.wikipedia.org/wiki/Fern_flower. Accessed 23 August 2023.
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