A Northumberland Alpine Gardener's Diary
This entry: 26 August 2007 by John Richards
Northumberland Diary. Entry 48.
One of my favourite trees is the tulip tree, Liriodendron tulipifera, which hails from eastern north America. This ancient magnolia-relative rarely flowers well this far north (although the 50 year old tree in our Newcastle Botanic Garden flowered heavily this year after last summers baking), but I love the amazingly shaped foliage, that turns butter yellow and cinnamon before leaf fall. I remember being told by Nick Nickou that it was an appalling weed in his Connecticut garden, as invasive as sycamores (Acer pseudoplatanus, not Platanus!) are here, but fruits never set here, so we are safe. However, when I planted one in our half-acre garden fifteen years ago, I was fairly sure it would outgrow its space, and we were finally faced to deal with it a couple of years ago. It already had produced bottom 'sprouts', so I thought it might respond well to coppicing, and so it has proved. Sheila cleared away the bottom growth last week, to reveal clean young shoots. The effect is attractive, if slightly 'poodle-like'. After leaf-fall we will need to cut it back to the stock again, and continue to do so every two years.
As you see, the last photo showed not only the tulip tree, and a young Davidia to the right, but also one of our 'sitting out' places (almost for the first time since April we have had some lovely 'sitting out' weather in the last few days) and some grass. We have quite a lot of grass, used principally to set off plants and for communication, but in large enough chunks to play ball games when our grandchildren visit. These days it is fashionable to do away with grass completely, but when we came here nearly 18 years ago we found nearly half an acre of grass and very little else, so the garden has been carved into the natural framework that surrounded it, and, I think, looks the better for it. I once wrote (Alpine Gardener 71: 267) that as a rough guide, gardens of less than 0.1 ha (about 30 m square) are better without grass, and those more than 0.2 ha are better with it. In general I still hold by this, not least because gravel top-dressing (the obvious alternative) is expensive in large quantities.
Not that I am an expert on growing grass; quite the opposite. Our grass is full of weeds, daisies, self-heal, creeping buttercup and some more exotic intruders. In the spring the effect is very pretty! In the more shaded areas, invaded by shallow lime-tree (Tilia) roots is also very mossy. On two occasions, I spoilt the lawn, and indeed the whole garden, for much of the summer by applying a general weed/moss killer with fertiliser. The moss (principally Rhytidiadelphus squarrosus, the one with little grapnels) went black for months, and the grass took all summer to grow in. Now I just feed the lawn in spring when I remember, which has not been for two years now! I cut it with a large self-driven rotary mower on wheels (with an automatic starter!), boxing all the mowings which I add to the compost. This beast is heavy, but is wonderful with rough undergrowth, of which we also have an area once the spring bulbs have finished.
In this area, our Eucryphia x nymansensis 'Nymansay' is flowering now, after a year off. If there is a more beautiful small flowering tree, I should love to hear of it.
In the last year, I have written very little about the two alpine houses. Both are aluminium alloy-framed affairs with lights in the roof and louvres, and were about as cheap as any glasshouses of this size could be. The original one that was put up as soon as we got here 18 years ago is the smaller, 12' x 8' (about 3.5 x 2.5 m). Although both houses are in the sunniest area of the rather shady garden, on the north boundary, the area is very sheltered, and bounded on that side by the neighbours hedge, so air-flow is less than wonderful. Consequently, fans run in both houses for much of the year. The doors are kept open, but have bead curtains to deter birds. This house has a rather unconventional arrangement for plunging pots, vertical pavers being held in position by wooden frames, filled with concreting sand. There is automatic watering by drip feeds, controlled by a time-clock valve. Although the whole arrangement looks very 'Heath Robinson', it works, and indeed has lasted well for nearly two decades without major replacements being necessary. This is the cooler, shadier and (with the automatic watering) more humid of the two houses. Gesneriads and asiatic primulas love being stood on the shady, humid floor.
The other house has only been in position for the last three years. It is larger (16' x 8'), in a sunnier position and is without automatic watering, so it dries out more readily. Also, the benches are more conventional, being essentially large trays made from 9" planks of treated pine, screwed together with stainless steel screws, stood on pillars of breeze blocks, and filled with sand. One side has nothing but bulbs, and is dried out in summer. Although repotted, few are yet in growth, which why one half of the house seems to be full of empty pots! The other side is half-emptied in summer, the saxifrages in particular being put into a cool plunge outside. Most have now just been brought back in again. A number of mediterranean-type subjects remain inside for the summer and are watered with a hose. Neither of the houses are shaded, and the smaller house doesn't need to be even in the hottest weather. However, I think I shall shade the sunnier house next summer.
More silver saxs
Conmtinuing from last week with the silver saxifrage collection, I thought I would feature S. hostii. This excellent, vigorous garden plant seems to be little known, at least under this name. We have grown it all our gardening lives, as we found it in a concrete tub in our first Hexham garden nearly 40 years ago and have taken it with us. For many years we didn't know what it was, until the forementioned (last week) Beryl put us out of our misery. I think this is the eastern subspecies hostii. It forms large hummocks over rocks which are attractive throughout the year, and if the flowers are less spectacular than some of its relatives, it definitely earns its keep as 'basic clothing' for the rock garden.
Four summers ago, we went to the Lake Garda region of northern Italy, and one day we drove west to the famous Passo Croce Domini. Amongst many other classy saxifrages, we managed to find a little of the highly localised S. vandelii (and lots of Primula glaucescens!). More conspicuous was the disjunct western subspecies of S. hostii, rhaetica. We were able to collect some seed, and this plant is sufficiently compact to grow in a pot.
I feel that S. hostii is probably related to another eastern limestone species, also found locally in the Dolomites, S. crustata. Again, this is not as seen in gardens as frequently as might be the case. Here it forms very attractive hummocks. The 'imbedded' limes glands on the leaf edge are diagnostic.
I see that the above photo also has a plant of one of the forms of S. cotyledon that I might feature next week.
I shall close with a pretty little Linaria that seeds about here. Originally we grew from seed in the same spring L. supina and the lilac L. anticaria and for some years the self-sown progeny were obviously hybrid, dwarf like the former, but with bluish flowers. These days, most of the survivors resemble L. supina more, but are none-the-less attractive.