Sarah’s Diary May 2025

May was a whirlwind of sun, soil, and serious plant action.

 I learned the magic of nematodes in pest control, mastered the fine art of planting Saxifraga longifolia into tufa with alpine legend Jim Jermyn, and tackled a tidy up in the Bulb House just as aphids were moving in. But the real showstopper? My first trip to the Chelsea Flower Show, an overwhelming floral fantasy filled with jaw dropping displays, inspiring conversations, and a proud moment representing the Alpine Garden Society. I even had a little Bajan pride moment at the Barbados Horticultural Society stand! Chelsea’s push for sustainability and biodiversity was heartening, and I left inspired. Next stop: native plant translocation with the RBGE Scottish Natives team!

Nematodes to the Rescue

While the heatwave continues to bake the beds and warm the glasshouses, the pests are having an absolute field day, populations are booming, and so is the need for effective control. One of our go-to biological solutions is the use of nematodes, particularly for managing vine weevil larvae.

We began by applying Steinernema kraussei, a species of entomopathogenic nematode effective against vine weevil grubs in cooler soil conditions, ideal for the shaded plunge beds and frames. The product arrives as a fine powder, which is then mixed with water to form a concentrated ‘nematode soup’. This slurry is transferred to a hose end sprayer that further dilutes the mix upon application, allowing even distribution across pots and plunge beds.

Timing is key, nematodes are most effective when applied to moist soil during cooler parts of the day, ideally early morning or late afternoon, as UV light and desiccation can rapidly kill them. It’s important to keep the soil damp for several days post application to allow the nematodes to move through the substrate and seek out their larval targets.

It’s a brilliant example of integrated pest management: effective, environmentally friendly, and oddly satisfying knowing that an invisible army is out there beneath the soil, quietly sorting out the troublemakers.

Tufa techniques with a master plantsman

One of the highlights of the month was learning the art of planting directly into the tufa wall, a specialist skill that blends horticultural precision with geological sensitivity. I had the privilege of working alongside Jim Jermyn, a renowned alpine plantsman and long standing contributor to the alpine horticultural community. With decades of experience in cultivating and exhibiting high altitude species, Jim generously shared his deep knowledge of tufa culture and alpine ecology, turning what could be a daunting task into a thoroughly engaging learning experience.

Together, we worked with Saxifraga longifolia, a species particularly well suited to this vertical, porous substrate. The process began with identifying suitable planting sites, specifically those with the correct angle and depth to promote strong root establishment. We prepared a planting mix of sand and finely crushed tufa, ensuring it was sufficiently moist to aid root contact and anchorage. Each plant was carefully transferred into a hand carved pocket in the wall, avoiding any damage to the delicate root system. Once in place, the cavity was gently backfilled with the same mixture, and the plant was secured using small fragments of tufa to hold it in position. This final touch created a seamless, naturalistic finish, allowing the plant to appear as if emerging organically from the rock face. The method was as meditative as it was technical, and under Jim’s guidance, I gained a new appreciation for the subtleties of growing in tufa and the patience and finesse it demands.

Tidying the Bulb House

This month also involved some important maintenance in the bulb house, which hosts a spectacular spring display of Iris, Tulipa, and Fritillaria species. As the bulb flowering season came to a close, much of the foliage had begun to die back and was attracting aphids, a common issue as declining plant material provides both shelter and easy feeding grounds.

Most of the bulbs had already gone over, so I removed the spent foliage and seed heads to tidy the beds and reduce pest harbourage. In general, seeds from these collections aren’t routinely kept due to the risk of cross pollination and unwanted hybridisation. However, seed may occasionally be collected and retained under ‘garden origin’ if the form is particularly interesting or belongs to a rarer species.

Following the clean up, the remaining plants were treated with SB Invigorator, a non-toxic, multi-action spray used to suppress pests whilst also supporting plant health and resilience.

A first time visit to the Chelsea Flower Show

The final and perhaps most exhilarating highlight of May was attending the RHS Chelsea Flower Show. This was my first visit, and what an experience it was! Hosted annually by the Royal Horticultural Society in the grounds of the Royal Hospital Chelsea, this world famous event is a celebration of horticultural excellence, innovation and inspiration. With a rich history dating back to 1913, the show is a cornerstone of the British gardening calendar, drawing designers, nurseries, plant societies and plant lovers from across the globe.

Walking through the gates for the first time, I didn’t quite know where to look, it was overwhelming in the best possible way. The layout of the show naturally draws you in. At its heart is the Great Pavilion, and when I say it’s the biggest marquee you’ve ever seen, I’m not exaggerating. Inside, it’s a sensory overload of colour, scent, and creativity. It’s where the top nurseries and plant societies show off their finest specimens, each display immaculately curated and often themed to perfection. I found myself wandering around in wide-eyed awe, exclaiming ‘wow!’ far too often… and mostly to myself … but it was impossible not to!

Winding around the edges of the show ground are the Show Gardens, the iconic full scale creations you see on TV and in the press. These are grand, sculptural, and often conceptual spaces, blending horticulture with art and storytelling. They’re stunning and awe inspiring, though for many visitors, they can feel a little out of reach in terms of what’s practical at home.

Tucked into other corners of the site are smaller scale balcony and container gardens, artisan areas, and trade stalls, plus, of course, all the pop-up cafes and fine dining experiences you’d expect from Chelsea. You’re never far from a glass of fizz or a £15 sandwich …!

I had the pleasure of spending time at the Alpine Garden Society stand, speaking with visitors about alpine gardening, the Society’s work, and my own traineeship at RBGE. Many people shared how much they appreciated the accessibility of the AGS display, unlike the larger, high budget show gardens (beautiful as they are).  Our stand demonstrated what could be achieved at home, even in smaller spaces. That sense of “I could try this myself” sparked enthusiasm in many, and it was rewarding to offer advice, show them the website, talk about the benefits of AGS membership, and even help sign up a few new members. Of course, I have to say how much I loved the AGS display itself. It was beautifully put together, full of character and charm, with miniature alpine scenes that really captured people’s imaginations. Each tiny landscape was like a world in itself, drawing people in for a closer look. There was something quite magical about it, proof that you don’t need vast borders or dramatic structures to create something truly captivating.

There were too many highlights to list, however I was especially excited to come across the Barbados Horticultural Society’s exhibit, something I wasn’t expecting at all. As someone who’s proudly Scottish-Bajan, it was a real joy to see a bit of my island heritage represented on the world stage. I couldn’t resist getting a photo with both the display and the President of the Society to send back home to my family in Barbados. It was a moment that made Chelsea feel even more special.

Sustainability Initiatives

It was heartening to see some moves towards improving sustainability, conservation, and biodiversity at Chelsea this year. The RHS has clearly put effort into reducing the environmental footprint of the show, switching to biofuel generators, sourcing mains power from renewables, upgrading to LED lighting, and even installing vacuum toilets that apparently reduce water usage by up to 90%. Many of the show gardens also made space for wildlife with naturalised pollinator friendly planting, bird boxes tucked between borders, and cleverly integrated habitats for insects.

What I particularly liked was the RHS’s commitment to ensuring that these stunning gardens don’t just exist for a few showy days in May. They are designed with a second life in mind being relocated to schools, community spaces, and hospitals, where they’ll continue to offer beauty, biodiversity, and inspiration long after the marquees come down. The ‘Great sell-off’ on the final day allows visitors the chance to purchase from the floral displays reducing further waste, which I may have taken advantage of myself…

I came away from the show with a camera full of photos, and a strong desire to return next year, hopefully with even more to share. Chelsea is a sensational celebration of horticulture, and having the chance to represent alpine plants and connect with fellow enthusiasts made the experience all the more meaningful. Join me next month as I team up with the Scottish Natives team at RBGE, where we’ll be carrying out a translocation project, putting conservation horticulture into practice, one carefully packed plant at a time.