You like loganberries? You'll love tayberries

A hundred years ago in Santa Cruz, Calif., Judge J. H. Logan accidentally produced a brand new berry that the world soon came to know as the loganberry. The judge was seeking to breed better blackberries at the time, but a row of nearby raspberries unintentionally contributed to the experiment, and the first-ever cross between the raspberry and the blackberry (considered impossible at the time) came about.

Now the world has the tayberry, developed over the past 10 years here on the banks of the River Tay at the Scottish Horticultural Research Institute by Dr. Dereck L. Jennings, a Welsh plant breeder who chose to follow his profession in Scotland.

The loganberry and the tayberry are both crosses between the European raspberry and the American Pacific Coast blackberry, but the tayberry is considerably larger and more fruitful. It's not that Dr. Jennings did a better job than Judge Logan, but he had better basic stock with which to work.

Dr. Jennings explains it this way: ''Plant breeders build on the successes of others. Judge Logan worked with the best-known varieties of his day, and I worked with the best varieties known today. Both blackberries and raspberries have been improved over the last hundred years, so I had superior materials to work with.''

The result of these ''superior materials'' is a plant that produces deep purple berries that are half as big again as the loganberry. Cane growth is particularly vigorous, and the plants are somewhat more cold-tolerant (to around zero degrees F. or -20 degrees C.). Flavor is good, and reportedly berries are excellent for juicing and for jam.

Early commercial yields in Britain and British Columbia have been very promising.

Commercial opportunities for the tayberry lie, probably exclusively, in the more temperate West Coast regions of the United States for the time being. But home gardeners can readily provide the necessary winter protection that will allow them to fill their freezers with the home-grown berries year after year, such is the new berry's productive vigor.

Like all members of the rubus family, the tayberry produces fruit on canes that grew the previous year. It is the growth habit of these new canes that makes it relatively simple for the home gardener to help them through winters that are colder than they are genetically engineered to withstand.

The new canes grow out laterally and after a while their weight and length bends them low to the ground. Encourage this low-to-the-ground growth, so that in the fall they can readily be given some protection. Once the canes are dormant, evergreen boughs can be laid over them. Snow trapped by boughs will provide additional protection. Plastic garbage bags filled with sawdust are another option. So is hilling up soil over the canes.

In the spring the canes are uncovered and left for a few days to gradually adjust to being exposed to the weather once again. Then, preferably on a warm day when the canes are supple, raise them slowly and fasten them to a fence or to wires stretched taut between two posts. Here at Invergowrie, the canes are trained up at an angle and then out along the wires in both directions from the center.

Because growth is very vigorous here (canes readily grow 12 or more feet long), some 25 feet separates each plant in rows that run north-south. Each supporting fence is seven feet high.

The tayberry appreciates a goodly amount of organic matter in the soil. If you have the time and space, you could begin working up the soil right now by planting a green manure crop - say annual rye, which puts out tremendous root growth and therefore adds copious amounts of organic matter to the soil.

Till this into the soil shortly before planting the tayberrys in the spring or, if you wish, simply makes holes in the dead thatch in which to plant the young plants. Of course, this soil-building approach would work well for any other member of the bramble family, too.

The tayberry has been awarded a plant patent in the US. Propagation in North America is being undertaken by Sakuma Brothers, PO Box 427, Burlington, Wash. 98233.