Firstly an admission. I got it wrong, when I said that Crocus ‘Cream Beauty’ seemed to be sterile. This followed last year’s attempts to self pollinate it with no apparent success and discovering that there didn’t appear to be viable pollen producing anthers in the flowers. This year I had another go, transferring pollen on a brush from the nearby white Crocus ‘Snow Bunting’ onto the obvious orange stigma of the ‘Cream Beauty’, and just this week, I’ve found a lot of seed capsules have pushed through the now parched earth on this southerly slope.
There are nothing like the numbers of seeds you find in the capsules of Crocus tomassinianus, which naturally seeds so well, but I’ve scattered the orange-pink seed around in the area, so in a few years we might get some interesting white-ish variants.
Readers of previous posts will know that I’ve been experimenting with moving Narcissus ‘Topolino’ bulbs in the green, and having left their seed heads on, this week I noticed that several were starting to split. What’s interesting is that in the past I’ve noticed firstly that most daffodil flowers rarely have insect visitors, and that most varieties never set seed, even if the pods appear to swell – open them up and you’ll find undeveloped white unfertilized seeds, and very rarely the plump shiny black mature ones. In the past, the only daffodils which I’ve noticed have set seed have been the native Tenby daffodil, Narcissus obvallaris, which often has a few seeds in a pod. Of course if no seed are being set, then the whole argument of whether one should deadhead them or not after flowering becomes a sterile one. Presumably little in the way of energy and nutrients are lost on the developing seed pod, which is not returned to the bulb as the foliage dies down. Certainly I’ve tried to manually pollinate, amongst others, ‘Jetfire’, ‘Jenny’ and ‘Geranium’ with no success. But the striking thing with ‘Topolino’ is firstly that I did see both beeflies and bumblebees visit the open flowers in the spring, and secondly that on average they’ve set nearly 25 healthy looking seed per pod. This is the first example of huge cultivar variation which exists, let alone species or genus variations in our garden plants, which I’m going to point up this week.
Like supermarket produce, the main driver for the development of more garden plant varieties is novelty and visual appeal, with sometimes attractive scent being added to the list. Whether the plant actually thrives in most gardens, or even lower down the list of priorities, whether it sets seeds, or is of benefit to local fauna just doesn’t enter the equation. Which is a pity. From a biodiversity point of view I think gardens could be even better wildlife havens if more attention were given to these latter plant characteristics.
Whether the daffodil seed germinate well, and whether they produce a diverse population of bulbs will take a few years to assess, but since I like the short, early and pale nature of the flower, I shall definitely be giving them a chance.
Just before this, I’d been thinking about the comparison between sugar peas and broad beans in terms of pod set. Our early ‘Sugar Ann’ peas seem to develop a viable pod from every flower produced, whereas this year, we seem to be getting a very low percentage of viable pods from the broad bean flowers. Why?
Clearly there has been a lot of work done on this issue since broad beans are grown extensively as a commercial crop, although for exactly this reason of variable yields, the acreage grown in Europe is apparently declining. I found a paper specifically on this topic as well as much anecdotal, though not particularly helpful, discussion on gardening forums. It seems that it is basically a fussy plant, and any stress through weather, nutrient deficiency, overcrowding or inadequate watering will cause pods to fail to mature. Over the years I’ve watched different bumblebee species either feed from the flowers (and I’d thought presumably aid their pollination) ‘correctly’ through the flower opening, as well as other bumblebees which don’t have long enough tongues to reach to the nectaries this way, so pierce a hole through the base of the flower to access the nectar by a robber’s short cut.
I couldn’t specifically find out whether this latter action would cause the flower to abort, but did discover the surprising detail that all peas and beans are self fertile. Indeed with peas the flower becomes fertile a couple of days before it opens, so insects aren’t needed for pollination at all. But if this is the case, how was Mendel able to carry out his genetic experimentation with Sweet Peas? And some papers imply that as I discovered with tomatoes, although the flowers are self fertile, you get a bigger crop if cross pollination takes place. Interestingly a paper from Algeria where researchers observed and recorded which species of insects did most of the pollinating of their broad beans found that it was solitary bees, at over 50%, then honeybees, which had most flower visits. Only about 15% of visits were by bumblebees. My impression here is that I’ve only seen bumblebees visiting – you’ll know from my other posts that we have more solitary bees than ever this year in the garden, and occasional honeybee visitors.
One of the details I think I shall explore, before giving up on them as a reliable crop up here, is growing them at different spacings to avoid competitive stresses. The general consensus was 6 inches between plants, which on average is what I’ve managed, but one authority suggested 8 inches, and of course growing them in a block as I do, perhaps this could be even further increased, since most folk will grow them in a double row with a much wider inter-row spacing than 6 inches. Perhaps a bean planting measuring stick is required to instill planting distance discipline. At the same time I came across 2 other interesting articles. The first one giving simple practical advice on saving your own seeds, and which plant characteristics were inherited in a recessive or dominant fashion, and the second being pretty scientific, but giving the latest thoughts on what determines when a plant actually flowers. I was interested in what triggers this event, since this year so many flowers have bloomed very early in the season, but others (like honeysuckle) seem to be pretty much sticking to their normal timing.
This also led me to the discovery of Arabidopsis thaliana, or mouse-ear cress. This is the botanical equivalent, apparently, of the humble laboratory mouse, or Drosophila (fruit fly), in that for 30 years it has been at the forefront of research into plant genetics across the world, mainly because of its small size, ability to grow from seed to seed production in only 6 weeks, and the ease with which genetic variants can be created. It struck me from the photos I found that it looked very like our own problem weed, hairy bittercress (Cardamine hirsuta), and following this up discovered that indeed they are very similar. Moreover that last year a research scientist at Oxford University was awarded nearly £500,000 to study various aspects of the biology of hairy bittercress over the next 3 years. Click here. And I thought universities were struggling with funding!
Just this morning another example of natural variations in fecundity struck me. With the early apple blossom and fruit set, I’ve started to thin out the fruit. The variation between varieties is enormous. One, ‘Leathercoat ‘ has yet to flower; ever. Even after 5 years. Others have modest fruit numbers and seem to naturally thin down to something like the accepted normal spacing of one fruit to every 4 to 6 inches of branch, whilst others have the full complement of enlarging fruits at every fruit cluster.
To leave all of these in place would be far too great a stress on the tree, so I usually thin them by pinching out, just as they are getting to the small marble size. On a prolific tree, this can take 10 minutes or so per tree, and no doubt this is why the commercial growers often spray their trees with a hormone to achieve this (often using a variant of the plant hormone auxin, not dissimilar to that used in plant rooting hormones).
I’ll also mention here my 3 tips for anyone planning a fruit orchard featuring apple trees. Since it’ll be a long term venture good research is invaluable. I used ‘The Book of Apples’ by Joan Morgan and Alison Richards (for great background information on hundreds of varieties), and ‘The Apple Grower’ by Michael Phillips, which is a brilliant science slanted book, but still full of the practical advice of an organic grower from America. Finally, the advice of a local grower is really useful. I bought many of the varieties from Paul Davies of Dolau Hirion nurseries in Capel Isaac in Carmarthenshire. By the end of this year I should have a much better personal analysis of which varieties are performing well up here, so more later.
Fruit thinning is indeed a satisfying repetitive task which allows you to spot things, and muse. And lest you think it’s wasted effort, they would have to be picked at some stage anyway. The caterpillar below surfaced as I was working my way around one tree, the spiral training and height restriction of the trees definitely aids this fruit thinning. After a couple of minutes of staying on the top side of the leaf, it repositioned itself under the leaf where it’s paler colours and linear markings made it very well camouflaged.
Camouflage is clearly the principal survival strategy for most moth larvae and adult moths. One that I spotted this week during a spell of weeding around a young Hydrangea ‘Annabel’ in a shady part of the garden was one of the ‘Longhorn’ moths, Nemophora degeerella, which as you can see has incredibly long antennae, and wonderful gold and brown markings. I think that this one had recently emerged from its pupa, since it was very amenable to being photographed.
Most moths are just so well disguised that the only way to find them is to run a special light after dark. I did this for the first time in ages a couple of nights ago, since we were expecting a couple of families to visit the garden the following day. A mild wet night, perfect flying conditions for many moths, produced some lovely examples of really dramatic moths, which always seem to fascinate people who have no idea that they are so numerous or varied in appearance. The oft quoted misapprehension that most people have of moths still holds true – that they’re all brown, only fly at night, and eat your clothes. I’ll include my photos, from our DVD-ROM guide to moths, of 4 of those species which we saw on Monday, to highlight just how wrong this perception is. (Buff-tip, Poplar Hawkmoth, Elephant Hawkmoth and Peppered Moth).
The point I’d made to the visitors that moths’ very survival depended on them resting up motionless during the day was sadly illustrated later on, when one of the Poplar Hawkmoths decided to take flight. After a prolonged period of shivering to raise the temperature of its flight muscles to a level where they were capable of working efficiently enough to power flight, it eventually took off. It flew away purposefully and fast, but within 15 yards had been picked off by a swallow. I’ve never seen a swallow catch any of the butterfly species we get up here, but they certainly seem to spot the nutritional treat of a daytime moth, in no time at all. Indeed, in Australia the aborigines living in the Bogong mountains also realised the nutritional benefits of a very high fat and protein snack. The Bogong moth aestivates in caves in the mountains and every year the native Australians would capture them, roast them and enjoy the delicacy. Times have yet to become this hard in the Carmarthenshire hills for me to start experimenting with novel Lepidopteran cuisine.
Further to the above photo, it may be one of the most westerly records so far of this species in Wales, judging by the latest map of its distribution.