You give me fever

Dandelions in sunshine

Don’t let hay fever spoil your summer – ditch the grasses and try these easy plant swaps, says Liz Potter  

Hay fever is running amok this summer. Advice from the NHS – to keep windows and doors closed, not to bring flowers into the house and avoid going outdoors on sunny days – seems a little bleak. The suggestion that the problem could have been compounded by ‘No-Mow May’ and its sequel, ‘Let it Bloom June’, might have some merit. Brainchild of conservation charity Plantlife, the No-Mow campaign calls on Britain’s 20 million gardeners and green space managers to give mowers a rest, allowing grasses to flower and produce their abundant, light-weight pollen in the process. But while everyone else is making hay while the sun shines, Britain’s one-in-four hay fever sufferers are living in torment.

Weeds, too are enjoying their moment in the sun, as part of the current rewilding trend. Nettles for instance took a star turn in many show gardens at RHS Chelsea Flower Show this year – a key caterpillar foodplant for comma, red admiral, peacock and small tortoiseshell butterflies. However, nettle pollen can be another source of discomfort for the pollen-sensitive gardener at this time of year.

“During late May, June and July, the most significant plant allergen, by a large margin, is grass pollen,” says Dr Beverley Adams-Groom, Senior Pollen Forecaster for the School of Science and Environment at the University of Worcester. “There are many grass species and some are extremely widespread, so it’s difficult to avoid their light, abundant and wind-dispersed pollen. There are some lesser offenders at this time of year, such as nettle, dock, mugwort and plantain – but weed pollen affects far fewer people.”

Hay fever kicks in when the pollen count reaches 50 grains per cubic metre of air. On ‘Very High’ days, the count can reach 150+, prompting a suite of symptoms – itchy eyes, sore throats, sneezing and streaming noses – generated by histamines, part the body’s own immune system.

According to the NHS England website, this summer has been a bit of a stinker. Weekly visits to its hay fever advice page reached 122,650 in the first week of June, compared to a mean average of 115,676 in June 2022.

“We’re seeing lots of high-count days this year because the warm weather is very suitable for pollen emission from grasses,” says Dr Adams-Groom. “However, pollen production was initially assessed as average this year and the pollen counts we’re seeing are not excessively high. The real problem for hay fever sufferers is not so much the size of the pollen count, it’s more the perpetual onslaught of high-count days, due to the almost continuous good weather since the season began in late May.”

Local variables such as topography, planting and microclimate all have direct impact on the amount of pollen we’re exposed to. Proximity to fields of oil seed rape, cereal crops, a mature leylandii hedge or catkin-bearing street trees can all tip the scale into a summer of misery. Birch trees are among the biggest offenders, with pollen counts reaching 80-200 grains per cubic metre during tree pollen season, April to early May. Plane tree pollen is another spring culprit, especially in London: it’s hard to avoid those green clouds that rain down on Main Avenue in late May, causing the so-called ‘Chelsea cough’. In fact, says Dr Adams-Groom, these are not pollen grains but lightweight seeds falling – but equally irritating to the back of the throat.

Climate change is also having an impact. Unseasonably mild winters, warm springs and dry summers have led to grass growing more vigorously. Certain ‘mid-season’ species such as meadow foxtail, perennial ryegrass and cocksfoot are flowering earlier, leading to a longer, stronger growing season.

All we can do is top-up on our meds and wait for the grasses to run out of steam. “If the hot weather continues, then the grasses will become exhausted more quickly and we will have a shorter season overall,” promises Dr Adams-Groom. “Already, I’m seeing some evidence that this is happening, with grasses going over very quickly.”

In the meantime, hands-on gardeners can follow a few simple design and planting tips. “Although grasses are the main culprit behind hay fever, there are sterile forms that don’t produce pollen at all,” says Olivia Kirk, who specialises in low-allergen garden design. “Calamagrostis ‘Karl Foerster’ and ‘Overdam’ are a lovely upright choice; Pennisetum ‘Fairy Tails’ is very tactile; and Panicum ‘Shenandoah’ is very colourful and doesn’t produce lots of pollen. With all these ‘prairie’ grasses, avoid using them en-masse and instead weave them through a planting scheme. Don’t over-use. 

“Then, choose ‘perfect’ or monoecious flowers – that is, with a female stigma in the middle and male anthers ranged around the outside. These are generally insect-pollinated, with heavy, sticky pollen that won’t become airborne. More enclosed flower forms, where the insect has to work to get at the pollen, such as foxgloves, aquilegias and lupins are also good, as are double flowers, which are bred by substituting pollen-producing stamens for petals.

“Avoid some of the Asteraceae, such as sunflowers and chrysanthemums, whose pollen is also quite allergenic. Heleniums are not called sneezeweed for nothing! Or, look for sterile forms such as Helenium ‘Sahin’s Early Flowerer’. Geranium ‘Rozanne’ and Geum ‘Totally Tangerine’ are also sterile which means they’ll flower for ages.

“Keep hedges trimmed to stop them flowering, or go for female dioecious shrubs. Rosa mutabilis would make a wonderful hedge too, supported on a two-bar fence, with excellent wildlife value.

“Invest in a robotic mower to keep lawn grass short all the time. Your garden is your sanctuary and if you suffer from hay fever you shouldn’t feel guilty about not taking part in No-Mow May. I do No-Mow June instead, once all the dandelions have disappeared, so I can enjoy all the clover and buttercups.”

5 Easy swaps

1/Swap ornamental grasses for sterile cultivars. All grasses have potential to produce allergenic pollen, but there are sterile options including upright Calamagrostis x acutiflora ‘Karl Foerster’ – a Piet Oudolf favourite. It produces pollen-free flowers June-August (H1.8m x S60cm). Other options: Calamagrostis ‘Overdam’; Pennisetum ‘Fairy Tails’; Panicum ‘Shenandoah’

2/Swap annual sunflowers for a floriferous perennial. For height, avoid annual Helianthus annuus in favour of perennial willow-leaved sunflower, Helianthus salicifolius. Often grown for its foliage, the latter has smaller spreays of flowers August-September, attractive to butterflies and other pollinators (H2m x S1m). Other options: Gaura lindheimeri; Verbena bonariensis

3/Swap trendy birches for Amelanchier. Birch pollen is the second most significant airborne allergen in the UK after grasses. Swap white-trunked Betula utilis jacquemontii for Amelanchier x lamarckii (H6m x S12m) which has starry white spring blossom, colourful bronze leaves than mature to green and purple-black berries. Other options: Malus spp; rowan; female Ilex ‘Golden King’

4/Swap evergreen privet hedging for laurel. Ligustrum vulgare and L. lucidum bear innocent-looking clusters of white flowers that can be insect or wind-pollinated; both are high risk for allergens. Cherry laurel (Prunus laurocerasus) and Portugese laurel (P. lusitanica) are better options, with insect-pollinated spring flowers. Keep them to H1.5m. Other options: Beech; hawthorn; cotoneaster

5/Swap chrysanthemums for Helenium ‘Sahin’s Early Flowerer’. For pollinator-friendly colour in the garden, avoid allergenic chrysanthemums. Helenium ‘Sahin’s Early Flowerer’ has a similar sunny look but is sterile and will flower June to August. Good for a sunny spot, Hm x S50cm. Other options: Geum ‘Totally Tangerine’ and Geranium ‘Rozanne’ (both sterile); enclosed dahlias; foxgloves; lupins; aquilegias

This feature originally appeared on The Sunday Times website 7th July 2023

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