DRAINAGE

Arguably, apart from the extensive new plantings, the greatest impact made around the garden involves digging out effective drainage ditches. Every west coast garden in Scotland demands good drainage if the plants are to thrive. In the 1960s soon after taking on the lease of Larachmhor, major ditch lines were hand dug across the low garden. In the past 20 years the LGA has hired a digger on several occasions, to not only re-expose many of the old drains that had silted up, but also to dig out important new lines, adding in culverts. The most dramatic work was the creation of the new Zig-Zag burn that leads from beneath the massive concrete wall of the new road, down through previously waterlogged areas of fine large rhododendrons and out into the field well beyond the garden boundary, where it feeds in to an established cundy (a partly slab-lined major drainage channel). This mammoth task, undertaken with the estate, has transformed, or rather rescued, this area of the garden, and now affords exciting new planting opportunities. Clearing out, enhancing, and where necessary re-routing drains around the site is a vital ongoing management task, and we are very fortunate to have a team leader who has great expertise with this specialist equipment.

DIGGING DEEP

Digging works, some undertaken by the estate have greatly widened and improved the main driveway, and also improved the line and base of some of the key feeder tracks. The main bridge undergoes periodic reinforcement with fresh recycled sleepers and other minor bridges are progressively linking pathways across the growing network of ditches. Significant additional heavy works have taken place around the bothies adding verandahs, complete drainage systems (with some of the roof water being captured for both domestic use and also for horticultural purposes.

Without regular attention the exotic plantings that make the garden would rapidly be out-competed by the semi-natural vegetation. The ever-extending high canopy progressively starves the exotics of adequate light. Crown lifting is essential to allow sunlight to filter down to the precious plants below. It is also necessary to remove dropped or damaged branches and fallen trees as well as selectively to thin out material to prevent overcrowding. This vital work was originally carried out with just hand tools, but from the early 1990s, the advent of powered chainsaws, strimmers and brush-cutters has transformed the team’s ability to undertake these tasks. It is noteworthy that the felling anew, or the clearing from already fallen, of a full-sized mature beech can easily occupy of team of some 6-8 volunteers (including at least 2 chainsaw- wielding members) across a couple of full-on weekends, before its crown and smaller branches are dragged and disposed of via a bonfire, its larger branches are sawn for the timber store, and its massive rounds are sliced and moved ready for future axe work.

Of course it’s not only the exotics that benefit from improved light penetration; bramble, bracken and other vigorous weeds rapidly invade any open spaces and require recurrent control. Selective application of herbicides is essential to control recurrent regeneration of the natural sward, as young specimens struggle to become established; it is also used to to keep the main trackways clear of vegetation. The annual programme of weed control can only be carried out in relatively calm, dry conditions, which all too often fail to coincide with the presence of relevant certified team members at the garden.

ONGOING ACQUISITIONS

Whereas Holms shipped his 200 plus specimens up to Arisaig principally by rail, the equally numerous plants that have arrived in the 21st century come in vans, on trailers, or quite often emerge from the piles of kit in the back of volunteers' cars. Although the flow of material direct from RBGE sources has now eased off, this influx of excellent wild origin material has been well supplanted by regular lots from expeditions undertaken by team members.

Curator Ian Sinclair’s travels in the Sino Himalaya and in north-west America have yielded many significant additions to the collections, as did the extensive (and ultimately fatal) Asian plant hunting travels of the late Jamie Taggart, a generous contributor of many previously unrepresented species of rhododendrons, many of which are just attaining flowering size.

Further major acquisitions continue to arrive through collaborations with members of the Rhododendron Species Conservation Group [RSCG].

New specimens arrive in a variety of sizes, and are sometimes grown on safely until suitably   robust for planting out. Large planting holes are enriched with compost, and in some cases the base area is weed matted. Where required, unstable plants are given stake supports, and in vulnerable locations will be surrounded by protective caging to prevent browsing damage. As a plant matures, periodic irrigation, weeding (by hand or chemical) and feeding (fish, blood and bone-meal is a staple supplement) are key components of the annual cycle of husbandry.

Prime mature rhododendrons and select other shrubs benefit from regular dead-wooding and dead-heading of spent trusses; but across a site of 28 acres, with a sporadic workforce, such  intense plant management is not really practicable; instead various pockets of the plantings get a short burst of such indulgent treatment now and again.

PROPAGATION

As time and available expertise permit, selected elite specimens are targeted for propagation. Over the decades air-layering, ground layering and the taking of cuttings have all been pursued, with mixed success, but some fine specimens have been successfully replicated, with opportunities to be bulked up on site, or exchanged with fellow enthusiasts. More recently, seed propagation has been attempted, with fertile pods collected, carefully cleaned and sown off site in certain members’ specialist facilities; but as most rhododendrons are somewhat promiscuous out-breeders, not all of the seedlings reared develop true to their source plant.

MAPPING THE GARDEN

A crude outline of the formal 19th century plan of the nursery garden can be found by zooming in on the 6 inch 1873 map sheet of the area, the basic elements of which underpin the subsequent layout. The RBGE team drew up an outline sketch of the site, subdivided into numbered planting zones. Team member Bob Mitchell (subsequently Curator of St Andrews Botanic Garden) began to mark the location of each of Holms surviving specimens, along with those of new plantings being added, as Margaret Hedge compiled meticulous card lists of the plants in each zone.

In the late 1990s an informative axial projection (almost 3D) plan was commissioned from skilled highland map-maker the late David Mason ARIAS, who had also systematically plotted each of the four gardens of the RBGE. His beautiful outline and coloured artwork has now been digitised and is the basis of both the Visitor Map and the Planting Zone plan that are used to determine ongoing management of the landscape, and to record the collections and their locations.

PLANT RECORDS

Just as John Holms kept a sequence of informative planting books, in which each new acquisition was numbered and logged, with occasional additional notes on its form, so the RBGE team set up a similar Planting Book. With the advent of accessible and portable computers in the 21st century, the current LGA team is systematically, but slowly, logging the GPS location of each exotic specimen, with information on the provenance (especially the collector, the country of origin, the date of collection) and of course its verified identity, where this is clear.

At present the LGA spreadsheet of Larachmhor’s plants runs to nearly 400 entries, as this herculean task moves inexorably and painstakingly forward. In tandem with building a definitive record of the entire collection, confirmed specimens are being labeled. Now and again early 1920s Holms-era labels are found, including dye-punched, elegantly hand-scratched, and acid etched versions. The LGA has trialled a number of systems to apply clearly legible names to major specimens and is now adhering to the use of wired (or for herbaceous plants, ground-staked) Alitags with legends applied as self-adhesive tape from a hand-held, battery-powered printer. These are proving cost-effective, very durable (to date) and have the great virtue of being generated in situ at the garden.

WHAT’S IN A NAME

The assignment of accurate names demands particular expertise, which the RBGE background of several core team members affords. However the naming of rhododendrons is a rather arcane specialism and demands exclusive knowledge. Over the decades we are fortunate to have been able to draw upon the unrivalled insights of such doyens of rhododendron taxonomy as (the late) Mr H. H. Davidian and Dr David Chamberlain (both of RBGE) as well as the talents of the RSCG and SGS, which include the current Larachmhor Curator. It must be acknowledged that when examining some of Larachmhor’s exquisite but less familiar mature specimens, especially the hybrids, this array of experts does not always concur!