Allergen-proof your garden with plant and design choices

Fiann Ó Nualláin looks at how you can allergen-proof your garden in plant and design choices

Breathe easy gardens

ACCORDING to the European Federation of Allergy and Airway Diseases Patients’ Association, over 80 million people in Europe currently have some form of allergic condition. From food intolerance, reactions to pet hairs, sensitivity to ingredients in soaps and shampoos, the predominant life strategy is avoidance of the triggers. When it comes to gardening there are several potentials for allergic reaction.

At some point in your life, diagnosed allergy sufferer or not, you will have encountered phytodermatitis (plant contact irritation). Some plants like nettles will cause a reaction to every individual they come into contact with, while others like Chrysanthemums may cause a rash to some gardeners but not to others.

There are three types of Phytodermatitis; irritant, allergic and photosensitive. Irritant dermatitis beyond the acute category of nettle sting also has a chronic side, triggered from repeated contact with prickly or thorny plants (including roses) where episodes of redness, itching and even blisters occur from a slow sensitising, much in the way most allergies develop.

Allergic dermatitis is triggered by handling a plant substance that you are allergic to — some plants contain irritant components in high enough concentrations to affect the general population and others in lower concentrations only affect a reaction in the sensitive portion of the population.

If you have a food intolerance for cashew nuts or mango you will have a sensitivity to any encounters with urushiol (the chemical component of poison ivy), present in low quantities in ginkgo and alstromerias too. Some bulbs trigger reactions via calcium oxalate, including daffodil and hyacinths. If anyway sensitive, avoid Primula, Euphorbia, Chrysanthemum, Rhus spp and Zantedescia.

Photocontact dermatitis is triggered by a reaction of sunlight to a residue of a phototoxic plant on your skin. Weeds like Giant Hogweed (Heracleum mantegazzianum) release a sap that blisters the skin while contact with garden staples like

Rue, Sorrel, Oleander, Sanguinaria, Boxwood and Yew can trigger photosensitive rashes and blistering.

The World Health Organization’s 2007 Global surveillance report on respiratory health concluded that worldwide an estimated 300 million people suffer from asthma. Nearly 500,000 of those live in Ireland. The major culprits of garden triggers for asthma are inhalant sources: Fungal and mould spores, plant spores, insect and animal dander and of course pollen grains.

Precautions for asthma are beneficial to hayfever and other sinus and respiratory complaints. Avoid ferns and other spore- bearing plants. Avoid bog gardens, stagnant water and pots in shady spots where mould accrues. Avoid working with wet mulch, raking damp leaves, and home-composting: aspergillus fumigatus, a natural constituent of soil and compost heaps has been found in the phlegm of many asthmatics.

Allergen-proof your garden with plant and design choices

Don’t rush to cover your soil with woodchip or other organic mulches that may promote spores and moulds, opt instead for gravel or groundcover plants. Avoid plants prone to mildew and other powdery diseases that could be inhaled. In fact, select virus, disease and pest-free plants exclusively if you can. Limiting chemical usage will benefit your health and the natural environment of your garden.

Introducing plants that attract birds, for example, a female tree with edible berries, will limit insects and their dander from your garden and also at nesting time, remove good quantities of animal hairs and other detritus. Keep on top of insects via organic methods and keeping plants healthy. Sick and neglected plants attract insects and insect secretions or “honeydew,” is a primary host for many moulds.

Note: Moulds and fungi are active in all seasons other than frosty winters while the pollen season starts in February with the tree pollens then lulls a little in mid spring but rises again with the prevalence of grass pollen from late May to mid-August, and even if you cut your grass regularly to defer it flowering, grass has the capacity to flower at various heights.

Limiting lawn area is a good option and it can be outright replaced with paving or squeezed by widening your borders filled with low and no-pollen plants. Most weeds and many wild flowers release their pollens from June to late September.

Avoid trees with catkins as they evolved to disperse massive amounts of pollen into the air and avoid wind pollinated garden plants, it is not just a case of opting for bee pollinated plants but plants which flower in the shape of bells and trumpets so pollen is enclosed. i.e Campanulas, peonies, lilies (if lightly fragrant as fragrance can be a trigger with some). Also, consider doubles and female plants. Female plants produce no pollen. Most hybrid plants are effectively feminised clones.

You do not have to miss out on your favourites. If you love Chrysanthemums (or other ornamental daisies) and it is not a dermatological trigger to you, then you can seek a double-flowering variety, or if you love roses, apart from varieties that bees have to climb into to get near pollen, most bear heavy pollen grains so any airborne dispersal will fall quickly from your breathable air. The great news is that you can have a garden of floral abundance and more diversity is good as it limits potential sensitising to a dominant species.

To help you get under way, here is a sample A-Z of some other low allergy plants: Antirrhinums; Aronia melanocarpa; Berberis vulgaris; Cranebill geraniums; Dianthus Daphne epimediums; Fuchsia; Helianthemum; Hemerocallis; Heuchera; Hostas; Hydrangea grandiflora; Iris; Kniphofia; Pachysandra; Papaver; Penstemon; Phlox; Physalis spp; Sempervivums; Viburnum; violas.

Most weeds and many wild flowers release their pollens from June to late September.
Most weeds and many wild flowers release their pollens from June to late September.


  • Don’t forget Carlow Garden Festival, which continues until tomorrow, if you want to squeeze in the last day. An initiative of Carlow Tourism, (hat’s off to them too, for an outstanding success), this festival has shot to the top of the must-do list for gardeners, nature lovers, tree-huggers and intellectually curious people all over Ireland. With an impressive list of speakers and demonstrators, including our own Peter Dowdall, the festival is combined with open days around some of the finest gardens in the country — so if you can’t make it this year, diary it for next year.
  • An Open Garden will be held at the Water Margin in Kenmare from August 5 to 7 in aid of Cork Simon. It offers an opportunity to explore the private, beautiful gardens of The Water Margin, Kenmare, set in one of the most scenic areas of Ireland. Located at Cappanacush East, Kenmare, it will be open to the public in aid of Cork Simon from August 5 to 7 August, between 2pm to 5pm each day. The gardens feature a river, waterfall and cascades along with informal planting with acers, azaleas, rhododendrons, hostas and astilbes. Plants and ceramics will be on sale and refreshments will be served throughout the weekend. Entry is by donation to Cork Simon, at the gardens. Directions: 4.5miles/7km from Kenmare. Look for signs at Templenoe on N70. Parking nearby. See:, phone 021-4929415, or email
  • Special Introductory Membership Offer for new Members at the RHSI Russborough Garden Show. The First RHSI Russborough Garden Show is taking place today at Russborough House near Blessington, Co Wicklow and to mark the occasion, a once-off introductory membership offer of one year’s subscription for only €40 — a saving of €15 for the year — will be available to new members at the RHSI Hub, in the Show Grounds. Membership benefits include free entry to RHSI partner gardens; access to member-only garden tours, lectures, workshops and floral art demonstrations and 3 copies per year of the RHSI Journal, which is full of excellent articles, garden reviews, news, gardening advice and tips. Members will also receive a regular newsletters about events and private garden openings and about volunteer opportunities. Gift memberships will also be available at the same special price. Remember to bring your RHSI Membership Card if coming to the show, as that will reduce the entry fee to just €6 — a saving of 25% on the entry fee.
  • Your help is needed for the All-Ireland Online Ladybird Survey of 2017. It is a citizen science project which means that the public is needed to get involved and populate the survey between the months of April to October.
  • If you are in your garden, going for a walk, or at work and you see a ladybird, then you can help. Leave it on the plant/place where you found it, but take a photograph. Make a note of date, time, and a brief description. And finally, visit and record your sightings. Photographs are very important as they help to verify records. For more information, contact or 089-4429013.


  • Docks and ragwort can show this month, the latter a noxious weed demanding removal. However, the dock, if not let flower, can be dug up, and boiled to accelerate compost heaps
  • Deal with plum rust, pear leaf blister mite and pear rus. Deal with woolly aphid.
  • Ventilate green house and poly tunnel and also cloches if still in use.
  • Try a nettle and comfrey tea blend for beans and peas as a boost this month, either foliar or watered in around roots
  • Continue to earth up main crop potatoes, celery and leek
  • Hang wasp traps to prevent burrowing into apricots, peaches and nectarines


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