What a coup!! You see those round little yellow tickets saying OPALS? They are there to tell you, on a scale of 1 – 10, how badly that flower and its pollen will affect you if you have hay fever or allergic asthma. And they are all over the gold-winning Birmingham City Council display at Chelsea Flower Show!
To be fair, its low allergy credentials were not the only thing in Birmingham’s favour when the judges did their rounds. The City Council had also joined forces with the Roland Emmet Society to create ‘A quiet afternoon in Cloud Cuckoo Valley’ featuring many of Emmet’s wonderfully bizarre creations – including this quirky little train which chuffed along the rail track stretched above the garden.
But, while Emmet’s creations were delightful, what we were interested in – and what it turns out the judges and the Royal Horticultural Society were interested in too – was the concept of low allergen gardening. (And just to reinforce the message, another part of the brilliantly colourful Birmingham stand with more OPALS tags…)
Anyone who suffers from hay fever or allergic asthma knows only too well what misery the pollen season can bring. But what most people do not realise is that, with some more informed planting of both our gardens and our public spaces, we could significantly reduce that misery.
As is so often the case, it all comes down to sex…. Male plants are keen to disperse their pollen (for which read sperm) as widely as they can – perfectly reasonably. And one of the ways that they choose to do so is by releasing massive quantities of that pollen into the air in the hopes that the wind will carry it far and wide where it will be picked up by female trees or plants wanting to be fertilised. Female plants wanting to be fertilised, suck that pollen out of the air and use it for their own purposes. But female plants also produce fruit, which, especially in town planning terms, cause a mess and a potential hazard, by falling on pavements. As a result, town and park planners and even garden planners have tended to go for male trees which will not create a mess. But while they may not create a mess, they do blast ever increasing amounts of pollen into the air massively increasing the allergen load for those who react to it.
Californian horticulturalist Tom Ogren has been putting this message out for the last 30 years (see his Allergy Fighting Garden, Safe Sex in the Garden and a whole series of articles on the FoodsMatter site). And in the process he has developed OPALS (the Ogren Plant Allergy Scale) which rates over 5,000 plants on a scale of 1 to 10, 1 being the least allergenic and 10 the most. His long term aspiration is that city and garden planners will change from planting male to female trees which would scoop the pollen out of the atmosphere instead of blasting more into it. But via the OPALS scale he is offering anyone and everyone the chance to improve their immediate environment by planting their own space with low allergen plants. And before anyone says, oh but they will be so boring and have no colour – just look at the two images of the Birmingham stand above. All of those flowers have OPALS ratings of 4 or less.
While Tom does visit us from the West Coast now and then, his baton has been taken up with amazing energy and success by Nigel Clarke who runs The Queux plant centre in Guernsey.
While filling all of St Peter Port’s hanging and window boxes every year and running Green Legacy Guernsey, Nigel is determined to turn Guernsey into the first allergen-friendly island in the UK. To that end he has created the OPALS tags that you see in the Birmingham garden, which he uses on all the plants that he sells. He also has a heavy breeding programme female trees, hedgerow plants, bushes and flowers.
But, Nigel is not content with merely ensuring that Guernsey becomes a low allergen island – he is busy converting the rest of the world! And through a series of fortuitous connections, he came to talk to Peter White, Deputy Chair of the Board of Trustees at the Birmingham Botanical Gardens – and through him to Darren Share, Head of Parks at Birmingham City Council who is responsible not only for all of Birmingham’s parks but for their stand at Chelsea Flower Show. Nigel is a persuasive fellow – and the cause he has espoused is a good one. Peter White and Darren Share were so Impressed with Nigel’s argument that public authorities had a duty to reduce the allergen load for those 20% of their citizens who suffer from either hay fever or allergic asthma, that they are now reviewing all of the parks’ planting policies. And as a first move towards this change of direction, Darren reviewed his planting scheme for this year’s Chelsea Flower Show to ensure that all of the flowers on the stand would rate at 4 or less on the OPALS scale.
And just fully to dispel the myth that low allergen gardening is going to be sad or depressing, these wonderful clematis, a new type also seen in the Grand Pavilion at at Chelsea, are rated at OPALS 3 (1 being the least allergenic, 10 the most)….
as are these totally amazing begonias….
For more detailed explanation of how and why pollen affects us so badly and what to do about it, see this blog or buy Tom’s Allergy Fighting Garden which includes an A–Z listing of 5,000 trees, shrubs and flowers with their allergen rating. For those interested in the town planning aspects of reducing the incidence of allergy, see Tom’s article here on the FoodsMatter site.
What you can do in your garden
Meanwhile, if you are a garden loving hay fever or asthma sufferer, do seriously look at the possibility of reducing the allergens in your own space. There is nothing you can do about the trees that are around you but just planting low allergen hedge around your garden will already start to protect you. All of the following hedging plants are low allergen and the lower you go (on the OPALS score) the better your protection:
- Weigela (3)
- Philadelphus – mock orange blossom (3 – doubles; 4 singles)
- Photinia (4)
- Crab apple (4)
- Escallonia (3)
- Hawthorn (4)
- Berberis (3)
If you want to have a lawn, make sure that you keep it mown short, always wear and mask when mowing and mow in the afternoon or evening; most lawn grasses release their pollens between 3am and 8am.
Do not grow grasses in your garden.
Before buying new plants, check then on the OPALS allergy scale (you will need to buy Tom’s book to get this) and check all your prospective purchases against the scale. Do not buy any plant with a rating higher than 4.
NB. For readers in London,specialist allergy and asthma nurse Shenagh Hume and children’s garden designer Jackie Herald will discuss London’s street tree planting with health in mind. Thursday 1 June 2017, 12.30pm -1.30pm Committee Room 3 at City Hall, SE1 2AA. This event is FREE.