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A Northumberland Alpine Gardener's Diary

This entry: 29 July 2010 by John Richards

Northumberland Diary. Entry 155.

Going potty

This is the time of year when I face the great annual crisis. What shall I do with all the seedlings? I have laboriously sown more than 100 packets of seed after Christmas, brought the seedlings into the alpine house as they germinated, watered and fed them, put them in the sun or shade depending on the weather, pricked them out , mostly individually, into small pots, fed, watered and moved them again, and, hey presto, its the end of July and I have hundreds (more than 400) strong and healthy plants crying out for a more permanent home.

For those of you further south in England who have endured a hot and dry summer, this may sound like boasting, or an impossible dream, but since the late spring and early summer, when it was warm and dry here too, this has been quite a good summer for seedlings, warm but not too hot, fairly regular showers, humid, and on the whole not too windy. Also, I am constantly amazed by the willingness of young seedlings to grow. Its like the young of any other species, animals too, or even humans, this amazing capacity to grow and thrive against seemingly impossible odds. Given the right conditions,  difficult alpines like Primula sonchifolia, Primula bracteata, Androsace brevis, A. rigida or Meconopsis lancifolia, to name a few that have done well this summer, grow apace and look so healthy when young. As in our own species, the problems arrive with adolescence!

So what is the problem? Well, if they stay in their small pots much longer, even if fed with dilute tomato fertiliser, many will start to regress from this point on. Certainly, I have found year after year that if they stay in their small pots overwinter I lose most of them. I have tried standing them out, putting them on the floor of the alpine house, putting them in a sand plunge uncovered, but the survival rate is always low. The problem here, I think, is that I have no old-fashioned frames, but if I put them in a plunge covered by a large light, they still suffer.

Planting them out carries extra penalties. It depends on the plant of course. Meconopsis, primulas, asiatic gentians and their ilk suffer when I put them in the 'D' beds (partially shaded with humus-rich compost) because no matter what I do they are full of tree roots, so dry at this time of year, and they get outcompeted by bulbs as they come into growth in the spring. Vigorous, 'easy' alpines (and I should grow more) do alright as long as I water and feed them after they have first been planted into the scree, raised bed, crevice bed or tufa bed, but I only succeed with smaller, slow-growing 'miffier' alpines if they are introduced into troughs, of which more anon.

For the shade-loving subjects (asiatic primulas, especially petiolarids), the fishboxes are languishing at present in deep shade, probably not the most promising habitat for young upstarts, and the compost in many needs renewal this autumn.

So, this year, rightly or wrongly, I have adopted a new strategy. For mny of the more 'difficult ' subjects I have potted the strongest seedlings, usually in 'threes', into larger pots, mostly about 20 cm diameter, either plastic or crock, depending on the perceived tastes of the subject. They are placed outside on the north side of the house where they get a little direct sun, but not too much, and where I can keep and eye on them and mist them in the evening. They are standing on a scree path, and as is clear from the following picture, they are surrounded by that evil smelling weed (here) Geranium macrorrhizum, as I believe, and so far the evidence is in my favour, that the stinky geranium discourages pests such as snails, aphids and caterpillars (but not woodlice!).

The plan is to keep them here, as long as they continue to thrive, until they start to go dormant at the end of October. They will then be brought onto the floor of an alpine house where they will be kept moist but not wet, until they come into growth again. At this point, some may be suitable for exhibition, others will go into shady plunges, and some may be planted out in their 'threes' (one rootball) once the bulbs have started to die down. Well, thats the plan anyway! About 25 subjects have been treated this way. Lets have a look at a few; Meconopsis quintuplinervia 'Farrer's form' (one of three accessions of this species grown this year), followed by Primula tangutica and P. limbata.

Here are Primula cernua (left) and P. muscarioides (P. deflexa has also been raised this way), followed by P. scotica and P. sonchifolia.

This can easily get tedious for the gentle reader who will have already have accused me (not for the first time) of vaingloriousness, which undoubtedly precedes a fall where difficult alpines are concerned, so here is a light change of tack. As I have already said in these pages, I have adopted a strategy for some subjects which I perceive, rightly or wrongly to dislike root disturbance, of potting on the whole panful together. I particularly believe this to be true for gentians, and so far this year, G. oschtenica, G. orbicularis and G. hexaphylla seem to have responded well (G. orbicularis, treated this way last year, is for some reason flowering now). By way of illustration, here are this year's G. arethusae, potted on whole into a much larger pot and doing well so far.

Naturally, some subjects have been targetted at the alpine house from the start. These have been potted on singly. Because only one alpine house is active at this time of year (the other, without automatic watering is too dry at present), space is at a premium. A good deal of space was won by cutting back some Greek foliage subjects (for instance Stachys chrysantha) and putting them outside until the autumn to recover. This raises a question. Multiple potting is one thing (and potentially useful for 'variation within the species' or raised from seed' classes at the Shows), but if you are potting a treasured subject singly for the alpine house, how many do you keep? There are issues of variability the choice of a good form, and self-incompatibility, where more than one plant is needed for seed to set (and for primulas the chance of getting at least one each of pins and thrums). In the case of the 25 or so Primula bracteata agg. I have raised, some seed courtesy of Peter Hood, the answer is four. The bad news is, this may not be enough. The good news is, plenty to sell! Here are the chosen few.

The same issues arise with Androsace pubescens and Silene argaea, with the futher rider that I find these a good deal more diufficult to grow, so how many do you need to end up with one strong survivor?

This wasn't an issue with Androsace lehmanniana (from my own seed) and A. rigida, as I only had a few seeds, and two seedlings of each to play with!

As I said earlier, some seedlings, particularly the offspring of favoured exhibition subjects, have gone straight into troughs. This involves remove what surface rock there might be (home-made tufa, limestone or shale for crevices) along with assorted mosses, liverworts etc, digging a root-ball-sized hole and filling it with newly made potting compost. (I should have said earlier that all the subjects potted on this year have gone into essentially the same mix of John Innes 3, sharp sand, perlite and pelleted 'Growmore'). A hole is now inserted into this new compost and the seedling inserted and watered in. This has the additional advantage of bringing sunken soil surfaces back to the level of the container rim, particularly if the top-dressing is replaced after planting. Incidentally, if it remains dry it is vital that the troughs are sprayed with a hose during subsequent evenings. Here are seedlings of my Primula villosa and Papaver degenii treated this way

Other newly planted seedlings in the above photo are Androsace hedraeantha, Veronica thessala and Saxifraga pedemontana. Here is the poppy.

Despite the dangers mentioned at the start of this entry, I have planted some Meconopsis out that are too big to grow in pots. Here is the scarlet poppywort. M. punicea, (M. aculeata from my own seed and M. simplicifolia hve been placed just beyond). This is followed by three Meconopsis, M. dhowjii, M. grandis 'Early Sikkim (own seed), and M. wilsonii waiting to go in. The automatic watering has a bit of an overflow, and this damp patch is useful for putting 'seeedlings in waiting' in!

So, altogether a round 50 subjects have been dealt with somehow. Of these about half of those pricked out still remain in pots, either as potential replacments, or to sell. The great question is 'how much subsequent attrition will they suffer this year'! The remainder are either bulbs which stay in pots and most of which are now dying down (another 11 this year) or subjects I don't need here and which have either been planted at the Newcastle Botanic Garden or will be also kept to sell.

Not much colour as August approaches, so a few foliage shots to finish with. Shortia soldanelloides is now maturing in a peat block. (The v. magna in the next block loves shade and disappeared under the all-enveloping leaves of sanguinaria. I solved this by turning the block round!

I love this association growing in the vertican crevice between two blocks of limestone. Ramonda myconi, Saxifraga paniculata, Androsace vitaliana and A. lanuginosa.

Finally, Dianthus plumarius. Such a good foliage plant!

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