by Ian Chrystal
Many members have, I suspect, sown bee pollinated seed at some time or another and found the results uninspiring. Usually offspring are inferior to the parents, and plain even if from a variegated plant. However, hybridising is not difficult: it requires only time and simple equipment:-
a pair of small sharp nosed scissors
a strongish magnifying glass
a system for tagging
and material for hosta 'condoms'.
Select your prospective parents carefully. Look for good leaf texture as exhibited by, say 'Sum & Substance', 'Halcyon' or yingeri. If you want waxy leaves, try 'Donahue Piecrust' or Hosta pycnophylla. Red petioles should be produced by crosses with 'Regal Rhubarb', Hosta pycnophylla and Hosta longipes hypoglauca. If you wish to produce a variegated plant, the 'mother' plant should be streaked: 'Yellow Splash' and 'Neat Splash' are readily available in the UK and many others are available in the USA. Streaked plants also turn up in tissue culture: your 'Hosta' nurseryman may have one or two. Ensure that the vestigial leaves on the scape are also streaked: such plants should yield a proportion of variegated seedlings, even when bee pollinated.
To prepare the mother flower (pod parent), it is necessary to emasculate it on the evening prior to opening ie when the bud is swollen. A little observation will enable you to judge the right time. Carefully slit open the bud, cut off the petals and sepals, and snip off the 6 stamens complete with anthers, leaving only the pistil intact. By doing this, you will have removed most chances of accidental fertilisation. To prepare the 'father' flower (pollen parent), loosely enclose the bud on the evening prior to opening. A small bag or piece of nylon stocking will do. Ensure that no pollen beetles or ants are present.
The following day, pollen on the male should be checked. Warmth is needed for it to ripen and it is usually viable between about 65°F and 80°F, mid morning on an average day, but deteriorates rapidly at higher temperatures. Pollen may be ripened by bringing it into the warm, and it may also be dusted on to a square of paper, folded, and stored in a refrigerator for later use: it can remain viable even into the next season. Some people have even succeeded in freezing it. I understand it is possible to store buds for up to fifteen days in the crisper section of a refrigerator.*
The pollen is held in two sacs in each anther. Ripened pollen may be recognised by testing an anther, which should shed in powdery fashion. The stigma on the pod parent will swell slightly when receptive. However, when a droplet of liquid forms, it is no longer receptive.
If the pollen is ripe, snip off a stamen and use the filament as a handle. Brush the pollen on to the stigma at the tip of the pistil of the pod parent. Repeat every hour or two to improve the chance of success. Alternatively, use a fine brush to transfer the pollen. Note that pollen and stigma on the same flower are not necessarily receptive at the same time, when selfing.
Carefully record your cross immediately, particularly, if you have prepared several plants. Tag it straight away.
Some people use multi-coloured plastic wire (offcuts obtainable from the next telecom van you pass), but be warned that the colours may fade in the sun. An alternative is to use good quality jewellery tags (available at stationers) and write on them with a waterproof pen. Whatever the method, it is important that the marker is located where the pedicel (flower stalk) joins the scape, or the swelling pod may push the marker off. If flowers on the scape are in close proximity, it may be easier to remove some in order to facilitate tagging, and overcome the danger of overburdening the scape with the weight of the tags.
When recording, write the name of the pod parent first, followed by X and then the pollen parent. If the flower has been open pollinated mark it 'X BEE' to avoid confusion.
After ten days, remove the flower remains from the bottom of the growing pod, to avoid them sticking to the tags and possible contamination later. Seed pods take 8 weeks and more to ripen. If you have used a streaked mother plant, look for variegation on the pods as this increases the likelihood of variegated seedlings. Variegated pods on Hosta ventricosa and derivatives will not however usually produce variegated offspring.
In the UK, late season crosses will often have to be made out of the garden. Certainly, they will have to be taken in for ripening if the plant is in a pot, or the scape removed before frost and ripened in sugar water.
When the pods turn yellow, collect, label carefully, and store loosely in paper bags, one per cross, until the pods have opened. On no account should plastic bags be used, or the bags be closed: fungus growth will appear and spoil the seeds.
When the pods have fully opened, free the seed with a pencil, remove all trace of pod and other rubbish, and store in a fresh clean envelope, and seal. Keep only fully ripened seed.
Viability is variable: if the seed is not being sown immediately, place in a refrigerator or a cool room, until required, to stop dehydration.
Further Information
Paul Aden: "The Hosta Book' (publisher: Christopher Helm) has an excellent chapter: 'Variegation and Hybridising Observations'.
There are many articles on different aspects of hybridisation in various issues of the AHS journal.
AND FINALLY ...
Do not be disheartened if only a few of your crosses take. Some cultivars are shy to set seed, and after all the bees do have a few thousand years start on you!
*ZUMBAR: AHS journal - Fall 1987 page 55
The above article originally appeared in the 1995 Bulletin.
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