Swede-scented Lupin in the garden this summer

Peter Dowdall is smitten by the cottage garden favourite, immortalised in a Monty Python sketch.

Swede-scented Lupin in the garden this summer

Peter Dowdall is smitten by the cottage garden favourite, immortalised in a Monty Python sketch.

If, according to Katie Melua’s song there are nine million bicycles inBeijing, then there must be a multiple of that number of Lupins in Sweden. Hard to believe that what we consider a sought-after addition to any herbaceous or cottage garden is regarded as an invasive species in the Scandinavian country.

It all comes back to that question — what is the definition of a weed? The answer is straightforward, a weed is a plant growing where it is not wanted.

I’ve never visited Sweden but it’s been a long time on the ‘to do’ list and when I do visit, I think it will have to be during the months of May and June when there are fields of this weed in full bloom. I’ve seen the photos and the Instagram shots and my mouth is watering, that trip is moving further up the list.

I can understand how it must be a scourge, the same as any problem weed, but that doesn’t take from its aesthetic beauty, in the same way that I am blown away each year by the sight of our bright yellow fields of rape seed in full bloom, though the wind-blown seedlings can be annoying, uninvited guests in the garden.

It’s the common blue coloured Lupin, Lupinus polyphyllus which is the invasive species in Sweden and whilst it may be a sight to behold, it is taking a toll, like all invasive species and monocultures, on local biodiversity. The Karner blue Butterfly in Sweden feeds on a different species, Lupinus perennis and this is being outgrown by L. polyphyllus, as it hybridises with it so easily.

Lupins love light, sandy, poor soils and will clearly thrive when given the right conditions. Most of our gardens in Ireland contain rich, heavier soils and often the challenge here is the opposite to the Swedish one and that is that they can be difficult to get to survive from year to year.

The problem, I fear, lies in what goes on above and beneath, in other words our soil and our rainfall amounts. We feed the soil in our gardens, be it with shop bought or homemade composts, well rotten farmyard manure or similar and Lupins don’t like this.

If the crown of the plant comes in contact with this rich, organic matter it can often encourage rotting and a once-beautiful hybrid can cease to exist quite quickly.

So, to encourage good, long term growth, use plenty of horticultural grit around and beneath the rootballs of Lupins when planting and do avoid the clump, if incorporating an annual layer of organic matter.

It’s always a good idea to mark where they are with a label or bamboo, as during the winter you can easily forget where they are positioned.

It is the L. polyphyllus species which makes most of the garden hybrids available in garden centres and in the wild they are predominantly, if not exclusively blue or purple. Thus, seedlings of shop bought varieties are not likely to come true to the parent colour, but are more likely to be blue or on that spectrum.

The only feasible way to bulk up on a particular hybrid is by division during the winter months.

Thankfully, purple is probably my favourite colour and I am quite happy with my Lupins being different shades of that.

West Country Lupins are what you should be looking for in garden centres around the country at the moment, as they are without question the best performers in terms of flower colour, longevity and quality and at the risk of driving garden centre managers mad across the country, keep an eye out for ‘Persian Slipper’ in particular.

A visit to the Bloom Festival is a must for any self-respecting gardener or even garden admirer, as there is so much inspiration and so many ideas, you can’t come away without at least some of it rubbing off on you.

I spent the entire week at the festival this year and my head is overloaded, but an overriding memory of this year’s show was the mass planting of Lupinus ‘Persian Slipper’ in the Sculpture in the Park garden.

Designed by Ruth Liddle and Ken Folan of The Kildare Gallery, this garden acted as a showcase for Irish sculpture and illustrated to great effect how to use it in the garden. They hit the jackpot, in my opinion, with their plant choice.

Tall stems of pure blue flowers which fade to a bicolour blue as the flowers age are produced on stiff stems reaching to about a metre in height and the mass planting of this one hybrid worked superbly with the sculptures.

Please don’t be fooled by the pea-like flowers and pods, as Lupin seeds are highly toxic and are never to be eaten.

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