Not many professional gardeners have quite as many strings to their bow as James Alexander-Sinclair, the British landscape designer, RHS judge, television presenter, writer and general brains behind the gardening app/online magazine known as IntoGardens.

He is probably best known to Irish gardeners in his role as presenter of the popular garden series, The Great Chelsea Garden Challenge (where would-be designers competed to create a garden on Chelsea Flower Show's prestigious main avenue). Viewers may also remember his frequent television appearances as the friendly face of that same annual flower show's judging panel.

Alexander-Sinclair will be in Ireland later this month to give a talk in Altamont gardens as part of the Carlow Garden Festival. It's a measure of his popularity as a public speaker – he's well known for his easy wit and particularly British brand of playful eccentricity – that the event is close to being booked out. But if you want further evidence of the latter, then check out the cult series of YouTube videos, Three Men Went To Mow that Alexander-Sinclair has made with two of his fellow British garden designers, Cleve West and Jo Swift. Funny and irreverent, they show why Alexander-Sinclair is the man of the moment within the sometimes stuffy world of British horticulture.

A self-confessed layabout as a young man, he certainly didn’t expect to become a gardener. “I left school when I was 17 and didn’t go to university, but instead did a variety of low-paid jobs until my mid-20s.” Instead, it was Alexander-Sinclair’s sister who suggested that he try his hand at horticulture. To his surprise, Alexander-Sinclair discovered that he loved it, and in particular the process of designing and creating gardens. Since then, he’s spent much of his time working with clients around the world. “Not only is it exciting, creative work, but there’s also great charm in the idea that you’re doing something that will leave the world a better place.”

Landscape design remains his great love, despite his other parallel careers within the world of horticulture. As one of the Chelsea judges, what are the show gardens that particularly stand out in his memory? “Dan Pearson’s Chatsworth-inspired design at last year’s show is one of them, as is James Basson’s exquisite garden, which was inspired by the landscape of Provence. As for this year’s show, I really admired Hugo Bugg’s Jordanian garden, while I’m always a fan of Cleve West’s work.”

When it comes to the thorny topic of why so few female garden designers end up creating show gardens at events such as Chelsea, despite the overwhelming preponderance of women working within this field, or the surprising absence of any women from this year’s Chelsea judging panel, Alexander-Sinclair sounds a rare note of frustration. “The RHS can only work with what it’s got. In other words, if only a handful of the designs being submitted for any show are by female designers, then already the dice is loaded in favour of the men.” As to the possible reasons why women might choose not to exhibit or to judge at these prestigious events, he points out that it’s not everyone’s cup of tea. “For example, I don’t design show gardens . . . although never say never . . . [at present, as an RHS judge, he’s precluded from doing so at any of the RHS garden shows]. And being a judge can sometimes be quite confrontational; you have to justify your decisions, sometimes in the face of strong criticisms. Not everyone wants to be part of that process. But we’re doing our very best to get more women involved, both as designers and judges. ”

Now an established landscape designer, Alexander-Sinclair's large garden in Oxfordshire is a place where he enjoys experimenting with new planting ideas and design techniques. But he's also a keen garden visitor, something that he's long valued for its ability to provide fresh inspiration. A personal favourite is Bury Court in Surrey, which contains gardens designed by Piet Oudolf and Christopher Bradley-Hole. "It's an exceptional garden, and one that was formative in my own education as a designer; I first visited it in the 1990s." Another is Rousham House, whose gardens are the work of the famous 18th-century landscape designer, William Kent. "No colour, just this wonderful classical landscape and huge vistas." But great gardens aside, this eccentric Englishman also finds design inspiration in the most unlikely of objects. "I once designed a garden based on a paper clip". How did it turn out? "Very well," he says with a chuckle.

This week in the garden

If you grow camellias in pots, then it’s very important to keep these shrubby plants well watered throughout the summer months to ensure the proper formation of flower buds and a good display of colour next spring.

Don’t make the mistake of presuming that the rain will do the job for you, as the plant’s evergreen leaves can act like an umbrella, stopping water from reaching the roots.

Slugs have caused terrible damage in the garden this summer, their populations boosted by all the wet weather. If you’re sick of using organically-approved slug pellets that dissolve in the first heavy shower, and don’t have the stomach to go slug-hunting at night, then consider using a nematode-control such as Nemaslug, which is harmless to garden wildlife. Available from most good garden centres including mrmiddleton.com and effective for up to six weeks after application, you simply dissolve the powder in water and sprinkle it over your flower and or vegetable beds. See nemaslug.co.uk

Strawberry plants are now throwing out plenty of runners. Properly known as stolons, these will quickly root and produce new plants if given half a chance. You can help them to do so by gently pegging them down onto the soil or in small pots buried in the ground, so that they make firm contact with the soil. Ideally, never leave more than four or five runners per plant. Prune the rest off, along with any yellow leaves.

Dates for your diary
Saturday, July 23rd-Monday, August 1st:

Carlow Garden Festival , guest speakers include James Alexander-Sinclair (see above), Mary Keen, Diarmuid Gavin, June Blake, Dermot O’ Neill, Helen Dillon, Neil Porteous, John Massey, Gethyn Gibson, Gordon Ledbetter, Seamus O’Brien, John Grimshaw, Carl Wright, Thomas Pakenham, giving talks at a range of great Irish gardens including Altamont, Burtown, Lucy’s Wood, Newtownbarry, Huntington, Shankill Castle and others, see carlowgardentrail.com

Saturday, July 23rd (2.30-4.30pm):

The RHSI Bicentennial Garden Party will be held in the walled garden of Russborough House, Blessington, Co Wicklow, which the society is in the process of restoring, admission free, see rhsi.ie