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A Northumberland Alpine Gardener's Diary

This entry: 24 June 2017 by John Richards

Northumberland Diary. Entry 341.

A vetching question

Necessity, they say, is the mother of invention. In the context of our garden, rather it acts as a spur which goads us into action. In three weeks time we are open to the public (a local charity event, one of a number of Hexham gardens which are visitable on the purchase of a single ticket). This couldn't really happen at a worse time for us. By mid-July we are usually headed for late-season wipe-out (this is essentially a winter, spring, even autumn garden), and this has proved an exceptionally forward year, perhaps the earliest ever. When  I say that Meadow Browns and Ringlets have been on the wing here in Northumberland since June 10th, you will see what I mean. Consequently, I suspect there will be very little to see (colour). Further, this has been the time of year when our garden has decsended into terminal chaos, driven by public enemy numbers 2-25, but especially by PE no. 1, vetch, Vicia sepium.

This horrible thing scrambles all over the garden, sun and shade, woodland, rock garden, perennials, arising from deeply embedded thin branched spaghetti which is impossible to eradicate. It does respond to systemic herbicides, but unless one is willing to bite the bullet and also kill the 'host' through which it is twining, it is impossible to separate the two.

A particularly severe infestation has invaded the front rock garden (the area which acts as the frontispiece for this blog on the website, albeit photographed many years ago). The seat of the mischief are large cushions of Dianthus plumarius which have long since outgrown their usefulness and flower very sparsely (although the huge cushions are decorative). In any case, this is prime planting territory, and seedlings and growing on apace.

A third necessity arose from an overfull compost-heap, We badly need to start a new compartment, which means first emptying it of what is now prime compost, a call for a major renewal somewhere!

Here is a photograph of part of the infested area before work started.

You will see that the rock garden here is underlain by some attractive waterworn limestone that was in the garden when we arrived. Here is a section after I had ripped out much of the dianthus.

I need hardly say that in order to remove all the vetch roots, all the stone needed to be moved and lifted to make sure none remained. Here is part of the area after the weeds have (hopefully) been removed.

As will be seen, wherever possible plants were left in place, where this did not compromise removal of the vetch. My 16 year old Adonis cyllenea was a particular concern, and this has not been touched, In the end I had to move a clump of the tap-rooted Crepis incana, which has resented this deeply. Luckily I also have a large plant elsewhere in the garden and I suspect from past experience that the crepis will eventually overcome the trauma and will survive as root cuttings. Another subject that had to be lifted was a 20-year old multi-rosetted Ramonda myconi. This presented an excellent opportunity for division, and the six rosettes that resulted have each been tucked into separate crevive to give the appearence of a colony.

Once I was fairly confident that all the vetch had been removed, and all the relevant infested plants were out of the ground and the rocks removed, I added a sackful of Singleton's JI 3, a barrow of sieved compost from the heap, and some slow-release pellets from chicken manure, forked it all in, and after replanting what I needed (and a number of new seedlings and rooted cuttings), top-dressed the area with four sacks of chippings. Luckily it has rained most days since (the drought is over for the time being).

While we were about it, further up the same area I have been concerned for some time as to the size to which the Pinus mugo there has grown. This caused Sheila (who has a much better eye than me) to lop it back to less than a third of its area, while cleverly keeping its shape. The pine had been planted at one end of a rather shaded scree and had come to dominate far too much of the area. This has freed-up a substantial piece of stony ground; this scree was made of 30 cm of coarse gravel and nothing else, many years ago, and has largely impressed by its sterility, although a few things (Geranium macrorrhizon, Potentilla cuneata, Gypsophila repens, Cyclamen hederifolium and, suprisingly, seedlings of Daphne mezereum, have found it to their liking. Consequently, I relieved the compost heap of another two barrow-loads which I forked into the newly revealed scree, and have started to plant this area up too.

Heart in mouth

We now come to what may prove something of a technical triumph, only time will tell. One of the few Show plants I have which is really out of the top draw is my Daphne petraea 'Grandiflora'. I acquired this as a small grafted plant more than 20 years ago, and it was last repotted about 10 years ago, when it was successfully moved into a crock long-tom with a 22 cm diameter. As suggested in more than one book, the compost was liberally laced with small lumps of tufa and since then it has not moved from the pot or its alpine-house plunge. However it is fairly frequently given a dilute liquid feed of 'tomorite' in the growing season. It was magnificent last year when it received a certificate (while I was in dock with a detatched retina), but its showing this year was more lack-lustre, causing me to consider a repot.

I was firmly of the opinion that if it was removed from the pot, this would rapidly hasten its demise. Consequently, I resolved to sacrifice the pot and to double-pot it in new compost in a larger pot into which the roots could escape.

Heart in mouth

I have to say that the initial assault was surprisingly successful!

Behold the finished article! Pride probably comes before a fall, but at the time of writing the plant looks smugly satisfied, as is its owner.

Back in the garden

Here is what has proved a successful combination of two common natives, neither of which were planted exactly where they have ended up, Echium vulgare, and the foxglove, Digitalis purpurea.

Back in the garden

On the subject of large combinations (as it were, sounds like a seaside postcard!) here is a slightly more classy pairing, Cardiocrinum yunnanense and Meconopsis baileyi. Usuaully these would not combine, but the early season has brought the giant lily forward. The large mec leaves are non-flowering M. 'Lingholm' from last years seed.

Inbreeding depression

Mention of meconopsis reminds me to celebrate the super new book on Meconopsis in the garden, part-published by the AGS. We now have two extremely handsome volumes to celebrate this wonderful genus which through the activities of the Meconopsis Group, founded by Evelyn Stevens, and Kit Grey-Wilson's major input into the two books, is now enjoying a resurgence of interest. Unfortunately, climate change is not helping those who would like to grow mecs, especially in the South. Nevertheless, there are useful chapters on how best to grow mecs, including one from a successful grower in the South-East.

I agree with almost everything that is written here, and aspiring growers should read these chapters with care. However I must disagree with what is written about self-incompatibility and the effects of selfing.

Firstly, it is evident that most meconopsis, and probably all the monocarpic species (which die after flowering) are fairly self-compatible, that is they can set seed when self-pollinated. It is immaterial whether they can self-pollinate, because most have several flowers open together and self-pollination can occur between flowers. However, there are a few species which appear to be self-incompatible, that is they will only set seed when cross-pollinated between different individuals. In my experience this is true of M. punicea.

Second, although most meconopsis can self-fertilise, this not usually a good idea. It is much better to grow several individuals in a group as cross-fertilisation will lead to vigorous heterozygous individuals, while selfing will lead to inbreeding depression (caused by the exposure of deleterious recessive genes  in a homozygous condition).

Third, it is completely untrue, as is stated in the new book, that continued selfing will lead to a failure of self-compatibility. Self-compatibility systems do not work like that. However, it is more than likely that inbreeding depression resulting from continued selfing will cause systemic weakness that causes failure of seed-set. This is nothing to do with the incompatibility system; merely general debility!

Right! Having got that off my chest, a few more plants!

I am finding the gentian-blue Moltkia petraea increasing successful and have several plants. This one grows with Campanula pulla.

 

Inbreeding depression

Another success has been Campanula choruhensis, grown from seed last year. A large plant in the alpine house is still in bud, but a much small plant planted out into home-made tufa in a fish-box has started to flower.

Campanula choruhensis

One of the quirkier experiments  has been with Hypericum grandiflorum. This large-flowered scrambling shrub grows in the Canaries. I gathered seed from northern Tenerife the January before last, and last autumn planted several seedlings out. Not surprisingly, these did not survive the winter, nor did a plant in the conservatory which did not appreciate the dry atmosphere. However, a seedling in a pot in the unheated alpine house flourished, rooting out of the pot. Consequently I have planted this out, pot and all, into what passes here for a hot border, and it is flowering freely.

Hypericum grandiflorum

The afore-mentioned border is south-facing, in front of the alpine houses and is mostly made up of sand. Like the rest of the garden it suffers by receiving no sun during the depths of winter, but in summer months these beds can get quite hot. Plants tend to be slow-growing in the sterile medium, but some dianthus have flourished. Here comes another grouse. What was grown about four years ago as D. alpinus proved to be border pinks! Actually, I like border pinks, they smell great and I have kept the best ones. Then, seed from last year as D. alpinus albus proved to be a white maiden pink (D. deltoides). Also from last years AGS seed I grew what comported to be D. myrtinervius. This is less straightforward as D. myrtinervius from the Makedonia-Greece border is not much more than a highly condensed D. deltoides, in the case of the wonderful var compactus, introduced by MESE from Kajmatkcalan in 1999, a tight cushion. I am inclined to think these plants may in fact actually be a poorish form of D. myrtinervius, worth growing but not a patch on v. compactus (this is the pink dianthus). The Allium is A. narcissiflorum..

To finish with, a couple of plants from the alpine houses. Planted out in the sand-plunge, Verbascum 'Letitia', that great cross between Turkish V. dumulosum and Cretan V. spinosum, raised by Ken Aslet at Kew, a great success.

Verbascum 'Letitia'

Finally, Saxifraga vayredana, grown under a lump of home-made tufa.

Saxifraga vayredana
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