A North Wales Alpine Gardener's Diary
This entry: July 2014 - Entry 23
Seed collecting in the garden
By mid-July most alpine plants have ripened their seed and will in many cases shed it very quickly if you fail to get to it first. I used to collect seed from a very wide range of plants in my garden and divide it between the varous seed exchanges (AGS, SRGC, NARGS), keeping some for friends and myself, but in this as in many other ways I am gradually easing off, and I now only collect seed of plants that I feel other members of the aforesaid societies might wish to grow and which are unlikely to be donated by many contributors. I am ashamed to say that there is no real method in what I collect; I do not have a carefully prepared list or plan, rather I grab seed when I can as I go around the garden doing various tasks, or during my morning or evening stroll to enjoy the garden and plan future endeavours. This laissez-faire approach requires that one always has the necessary items close at hand, so I keep seed packets, pencil, tweezers, scissors and a couple of old tobacco tins in the alpine house where I can grab them at a moment's notice on spotting ripe seed needing to be collected. If it should be raining, or the seed pods and/or seeds are wet, unless they are about to be shed I will wait until they dry out, as I find drying wet seed successfully to be a tedious task and therefore best avoided.
Seed comes in all shapes and sizes and varies considerably in its ease of collection. Best of all (as long as you grab the seed before the wind takes it away!) is that of the dandelion family (Asteraceae), some Rosaceae, pulsatillas and others, whose seeds being wind dispersed will detach readily from the receptacle when ripe and can be quickly popped into an envelope without the need for cleaning, although you may need to go through it later to separate the fat (viable) seeds from the thin (non-viable) ones.
Almost as easy to collect are seeds which are born in closed fruits that open by some sort of pore or split when the seed is ripe, by which time it is usually free within. These can be carefully detached from the plant and either held over a collecting tin or other receptacle to allow the seeds to fall out, or the whole fruit can be placed in the tin or envelope for separation from the pod later; aquilegias, poppies. and many bulbs are good examples. Gentians fall into the same category, although you may need to 'help' the seed out of the pod as it is generally less free flowing. I snip off the pod with a length of stem in such cases and after placing the mouth of the fruit in the receptacle I twirl the stem gently between finger and thumb, which throws the seed down and out of the pod.
Some seed, notably that produced by cushion plants, can often only be collected with a pair of flat-ended forceps, which can be a frustrating and time consuming task, especially when the seed falls out of the capsule and down into the cushion at the slightest touch! How I envy the patience and steady hands of those intrepid alpine plant collectors for whom this is a routine task on every seed collecting trip.
I always deal with seeds borne in or on fleshy fruits immediately I collect them, removing the flesh by gently squeezing the fruits in a sieve under running water, then drying them on kitchen tissue before putting them in seed packets; otherwise if the fruits are left for any length of time they will either rot or will go rock hard making it difficult to extract the seeds. Some seeds (alstroemerias, many geraniums and erodiums) are explosively dispersed as soon as fully ripe so if you mean to get any you must watch as the fruits develop and collect them in good time, but in some cases you can collect the slightly unripe fruits and place them in a closed paper bag or envelope when they will continue to ripen, eventually releasing their seeds.
Another group of plants, notably some asiatic primulas, many members of the buttercup family (Ranunculaceae), and trilliums and arisaemas have very short-lived seed which is best collected just before it is fully ripe and sown immediately; if stored for any length of time, even in a refrigerator, it needs to be kept damp (not wet) and even then it may not germinate when sown or will give poor germination rates. Speaking of refrigeration, I always place cleaned dry seed in the fridge as soon as I collect it and only take it out just before I sow it or send it to the seed lists or friends.
I generally aim to get my small stock of bulbs in pots (about 150 pots) repotted by the middle of August, but this year I have managed to complete the task before the end of this month. I use a potting mix (by volume) of two parts of J Arthur Bowers' John Innes No. 2 compost and one part of either perlite or grit, which seems to work quite well for me. As I attend to each pot I decide whether to turn the bulbs out, sort them and repot with new compost, or scrape the compost off the top of the bulbs and add new without disturbing the bulbs. This depends chiefly on how crowded the bulbs are, but is also influenced by the number of offset bulbs produced, if many then I will generally sort out the flowering size bulbs from the offsets and pot them up separately. Once potted the plastic pans are returned to their Access fram where they stand on sand which is never wet but never completelt dry either. Pans of narcissus and lilies are watered immediately after repotting as they make new root growth early, but the remainder (chiefly crocus, cyclamen and fritillarias) are not watered from above until I remove the roof lights on the frame during the first heavy rain in September. Bulbs that are not suited by this regime have to lump it, and some die, but others (e.g. some calochortus) survive and flower year in year out, though never increasing much. One genus that I have not so far grown in pots is Galanthus, all mine are planted in the open ground. This is not for any particular reason and there is no doubt that many people grow them very well in containers, as demonstrated by the wonderful pans of snowdrops that appear at the early shows; perhaps I will give them a try.
Pumice for cuttings?
I have never until now tried crushed pumice as a material for rooting cuttings, but having talked to various AGS members who swear by it I have decided to give it a go. Like perlite, it is porous so retains air as well as water, but is easier to deal with as it is not so light. I have so far only experimented with a coarser grade than I would like (2-4 mm), but that is all I could get hold of; it is not the easiest of materials to come by. I think that a 0.5-1mm grain size would be much better, holding the cuttings more firmly and requiring less watering to retain ideal moisture conditions. I have now found a source and will hopefully be able to get my chosen grade in time for next year's propagation season. I will let you know how I get on with my daphne cuttings in the coarser grade and should be very interested to hear of successes or failures of other growers using this material.
Some flowers in the garden now
There are still some nice things in flower at the end of July, chiefly campanulas, and C. pusilla (syn. cochlearifolia), though a very common plant both in the European mountains and in the garden, is by no means least among them. As the photograph shows, it will soon cover quite a lot of ground, and like most spreaders by underground runners is always best at the edge of the patch. There are quite a few colour forms available, including a lovely pure white, and in my experience all are good. One particularly attractive form is C. pusilla 'Elizabeth Oliver' which has densely double bells of a nice clear, pale blue
I have a huge plant of the pink 'dandelion', Crepis incana, which has been flowering its heart out this year. It must be 15 years old by now and never fails to please. It needs really poor, free-draining soil, which it gets on the raised bed which is its home, give it something richer and you will get an even bigger plant but with fewer flowers.
Whipcord arisaema - Arisaema tortuosum
A. tortuosum is a very widespread species occurring from the himalaya in Western China, southwards to N. India and Burma, where it occurts in forest, scrub and coarse meadows. Being so widespread it is variable in size (it can grow to 2 m, although 50 cm is more usual), while the colour of the spathe can vary from very pale green through darker shades to purplish green. Likewise the whip like spadix (hence the name), which usually turns abruptly upwards at its tip, can be green or purple. Unlike several of the arisaemas I have tried in my garden, this has turned out to be completely hardy and is forming nice clumps, but only where the soil is constantly moist; in drier areas of the garden it survives but does not prosper. Like all arisaemas, it is easily raised from fresh seed collected and sown as soon as the red berries begin to fall off the fruiting receptacle, much more difficult from dried and stored seed, if indeed it survives dessication at all.
Another arisaema that does quite well with me under similar conditions is A. ciliatum subsp. liubaense from Yunnan and Sichuan; all plants I have seen in cultivation have the nicely striped spathe borne about two thirds of the way up the 'stem'