Profligacy, Variations and Longhorn, Buff-tip, Poplar Hawk, and Bogong

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.

Seed capsule from Crocus Cream Beauty crossed with C.Snow Bunting 29/05/11

There are nothing like the numbers of seeds you find in the capsules of Crocus tomassinianus, which naturally seeds around 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 maybe 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. Of course 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.

All these seed…..probably more than 3,000, from just 200 Narcissus ‘Topolino’ bulbs, in their first year of planting..31/05/11

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?

Broad bean Witkiem manita, grown from saved seed. Healthy plants but of the 3 flower clusters here, with about 7 flowers per cluster, only 1 pod has set. 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 which you can read here if interested,( http://docs.google.com/viewer?a=v&q=cache:AbluvtYOBdUJ:ressources.ciheam.org/om/pdf/ ), 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.

A culprit caught in the act. Bombus lucorum cutting through to the nectaries and bypassing the flower

Punctured flower bases from short tongued bumblebee species activity 29/05/11

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% ov 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 instil planting distance discipline! At the same time I came across 2 other interesting articles which I’ll put links to here. The first one giving simple practical advice on saving your own seeds, and which plant characteristics were inherited in a recessive or dominant fashion(http://www.seedsave.org/issi/issi_904.html), 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. I’m going to insert the diagram below, which comes from this excellent review paper  since it shows just how complex the apparently simple task of deciding when to grow and open your flowers is for a plant species, with genetic and environmental influences all playing a role, but interestingly the basic control pathways seem to be common to many mono and dicotyledonous plants (single and double first leaves, e.g. grasses and other flowers) so obviously developed at a pretty early stage in the evolution of flowering plants. (http://www.flowercrop.uni-kiel.de/state-of-the-art-preliminary-studies-and-research-needs)

Figure1

Figure 1: Simplified scheme of genetic, endogenous (blue) and environmental (red) influences on flowering time initiation.

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. And I thought universities were struggling with funding! (http://www.bbsrc.ac.uk/pa/grants/AwardDetails.aspx?FundingReference=BB/H01313X/1).

But 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.

The scale of the thinning issue on some apple trees 31/05/11

To leave these all 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 longterm 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.

In a cluster you aim to leave just one fruit….always a wrench when they all look healthy, but lots of the time you can pick off ones with holes from moth larval damage, deformed fruit, or ones with rasped surfaces from snail activity 1/06/11

Some varieties seem to do the thinning for you…and also just now the organic apple grower’s battle with apple scab starts to become obvious, with deformed, blotched leaves 1/06/11

But it’s 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.

Cloudud Drab ( probably!) caterpillar 31/05/11 . You can find 25 -30 Clouded Drab moths per night visiting a moth light in our garden in March/April, but I’ve not seen the caterpillar before. Identifying caterpillars is a nightmare…’Caterpillars of the British Isles’ by Jim Porter is a good starting point, but I then cross reference with internet images

I’ve no idea, yet, what these 3 caterpillars hanging from a promising rose seedling which I’ve planted up in a tyre, are….28/05/11

Of course camouflage is 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.

Longhorn moth… Nemophora degeerella 28/05/11

But most are just so well disguised that the only way to find them is to run a light at night. 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. A mild wet night 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. I’ll include photos of 4 of those which we saw on Monday.( Buff-tip, Poplar Hawkmoth, Elephant Hawkmoth and Peppered Moth).

These 4 images are all taken from our DVD-ROm on Garden Moths ‘In A Different Light’

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 achieve take 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 aboriginees of 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…..

Backlit Astrantia major flowers 30/05/11

Clematis ‘Broughton Star’ and Honeysuckle 31/05/11

Heuchera and Primula flower froth 31/05/11

Since F recently found my misplaced Field Guide to the Bumblebees of Great Britain and Ireland, I can now identify this bumblebee as Bombus hypnorum, which was new to the UK in 2000, and in this book published in 2005 is shown as restricted to the South East of England. It seems to have made it’s way up here in the last 6 years! 31/05/11

Further to the above photo, it may be one of the most westerly record so far of this species in Wales, judging by the map of its distribution which can be found here for 2010(http://www.bwars.com/bombus_hypnorum_map.htm ). It’s certainly spreading fast throughout the UK.

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7 thoughts on “Profligacy, Variations and Longhorn, Buff-tip, Poplar Hawk, and Bogong

  1. Hi Julian,

    If you want the broad beans to set just go of on holiday for a couple of weeks! Prior to going virtually every flower was dropping off the beans in the poly tunnel probably due to temperature and water stress but now 10 days later they are nearly all setting in the poly tunnel and i suspect the weather was cooler whilst i was away.

    This year I have planted The Sutton outside and it is very short stemmedand looks to be standing up much better. At the moment the plants are covered with flowers – more than the plant can possibly support- so it will be interesting to see how many set.

    Dave

    • Hello Dave,
      How you manage such a good productive plot, when you’re always off on holiday amazes me…! But you’re right, my flowers now seem to be setting a bit better than the first few clusters. I even saw a solitary bee pollinating them yesterday,after saying it only seemed to be bumbles! But I reckon with all these reports of broad beans growing in the mediterranean, it may have been the colder nights we had recently which did for the flowers…though there seem so many possible stresses that you’ll never be able to pin it onto a single factor. Have you seen the Bombus hypnorum yet in your garden. I emailed the BWAR recording chap who confirmed that my picture was a hypnorum, and that Carmarthenshire is only just getting reports of it. The sun has returned in time for A to catch up with the washing!
      BW Julian

      • Hi Julian,

        We seem to have only bumble bees pollenating the broad beans both inside and outside the tunnel. Dont think I have seen the new bee yet but am not very good on bumble bee species.

        I think the problem with bbeans setting in the poly tunnel is the difference between day and night temps rather than specifically the cold nights. Water stress may also be a factor on hot days. Last year I tried some runner beans in the tunnel with very limited sucess. The Sutton broad bean is looking very promising.

        Hoping the sun will go away for a few weeks as meter is now nearly back to the Jan board reading That or will have to start using the fan heaters in the poly tunnel at night!

        Yesterday was best day ever for me -27.75

        Arrived back late thurs night with a cold and at least 4 loads have gone thro the machine allready!

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