Getting Bigger Faster

By Charles E. Tuttle

Hosta multiply too slowly, at least for some of us impatient types. A first year plant with one crown, becomes a two to four crown plant in year two, then a four to six crown plant in year three and so it goes each year; that is, if all goes well. We all know that it takes most cultivars four to six years, or more, to become a mature clump. There are numerous physical means of propagation to speed up the division process of the Hosta plant growing in your garden, e.g. Rossizing, the heel method, the lawnmower method, Zumbarizing, and others. Recently a new product has been introduced on the market that accomplishes this same goal - and in fact you may have seen the advertisement in The Hosta Journal and wondered what it was all about.

BAP-10™ was first brought to my attention this past March at Hosta College in a class taught by Ed Elslager of Ann Arbor, MI. Ed told us that BAP-10™ is a naturally occurring plant hormone (N-6-benzyladinine) which overcomes apical dominance then promotes the growth of new shoots. What is apical dominance? The central growth point (a/k/a the meristem) of a crown puts out an inhibiting factor which "tells" the other buds not to grow. This way there is not a mass explosion of new buds. Each year the plant follows an orderly pattern of crown growth and division. The apical dominance factor is a hormone and is "neutral" immediately after the flowers bloom. During that small window of time, dormant buds start to grow and develop and these buds will become the new shoots that will come up next year (and, remember that they, too, put out the apical dominance factor so that only a few of the new shoots grow that particular year - and so it goes from year to year). This new product sounded great to me. I am relatively new to Hosta and most of my Hosta beds have plants with only one and two crowns. Why not try it? The supplier gave Ed sample bottles of the product which he in turn passed along to class participants to experiment with.

An article which appeared in the May, 1998 issue of Greenhouse Grower, was sent to class participants by Plant-Wise Biostimulant Co, the maker of BAP-10™. This article tells the background of the research done at the University of Georgia and then at Auburn University and the response the hormone elicits in Hosta. It sounded like something just short of a miracle product. Why not try it?

Based on some information contained in the article, a mixture of BAP-10™ was made at the 3,000 ppm (parts per million) level (this is 15ml of BAP-10™ in a 500 ml volume of distilled water with one drop of Joy™ detergent added as a surfactant). The researchers used levels from 1,000 to 4,000 ppm in their studies. I sprayed this product mix on the leaves of quite a few cultivars with wide ranging characteristics - from mini Hosta to the large size plants of the sieboldiana family and the full range in between. The results were short of astonishing.

H. ‘Sun Power' is a favorite of many of us and I too have a one crown plant strategically planted this spring in full sun. On June 15th the leaves were sprayed (there were 11 petioles on the one crown) with a general dowsing and some of the spray ran down that nice little funnel that the leaves make where they attach to the petiole, thereby getting the crown itself drenched. Ten days later the shoots started to emerge. Two months have passed and most of the old petioles have died off, simply because the leaf buds swelled so much in making the new shoot, that they split and tore the petiole from the crown. Now there are over 14 new shoots coming from the crown of this one plant. Next year this H. ‘Sun Power' plant should look beautiful. This, granted, was the most dramatic response; however, the vast majority of cultivars sprayed have shown a response with four to ten new shoots. According to the above mentioned article, "BA can be applied at any time during the growing season to induce attractive new growth from stimulated offsets. Mid-summer applications can promote renewed growth at a time when growth of hostas is often slowed and plant decline because of heat stress.....BA application does not appear to have any negative effects on winter-hardiness or subsequent regrowth in the following season."

Another by product of this application is that those of us doing tissue culture can get a jump on the beginning process of getting an explant to put into production. The "normal" procedure is to wait for a crown to come out of dormancy in the spring (dormancy can also be forced with refrigeration), harvest the meristem from a new emerging shoot, sterilize it and place the prepared meristem on to tissue culture cell proliferation media. Now, with BAP-10™, new shoots can be generated throughout the growing season and the crown itself does not have to be sacrificed. There are plenty of shoots to choose from.

Is this product for everyone? I doubt it. It is fairly expensive at $175/liter and most small gardeners, who are not quite as obsessed as some of us, just do not have the call for it. Perhaps a group of gardeners who are anxious to get their plants growing bigger, faster, will go together and purchase the product and apply it to single and double crown Hosta in their gardens. It has made a big difference in my garden throughout the latter months of this summer and I am most anxious to see how they come up in spring 2000.

Ed reports that he is giving another class at Hosta College 2000. Now is the time to make plans to attend his class if this new process interests you.