Wednesday, April 15, 2009


At the end of the last post, "Bob's herb Garden" I asked what I was forgetting. Bob wondered about the three raspberry plants he took. Raspberry leaves are often used in herbal teas and for certain medicinal purposes, so qualify as herbs even if I wasn't thinking so.

The whole business of plant names really seems besides the point until you want to document them in one way or another. I've lost track of the names of lots varieties of plants,for example the names of some of my roses. These names are a little different from scientific names; they are names of varieties.

In seed catalogs often the term "hybrid" comes up. There are two somewhat different meanings of this usage. The first is a cross between two pure-bred lines. Explaining this stuff can get a bit complicated, so mine is a simplified explantion. One reason some flower and vegetable seed are hybrid crosses is because the off spring grown from the seed often displays "hybrid vigor." The most common sort of hybrid of this sort offered are F1 hybrids, standing for "Filial 1," meaning first offspring. If these are grown out and left to flower and seed, plants grown from that seed will not generally come true to type. This sort of seed is more expensive because of the labor of pollinating the crosses--often by hand. But the improved characteristics and vigor are often considered worth the cost. Another sort of "hybrid" offered results from a process of selection. Someone notices a particularly good plant of some sort. This plant is left to flower and seed and the resulting seed is planted with particular plants from that crop having the desirable characteristics selected and grown out and the seed collected. This process is continued long enough so that the plants grown from the seed grow "true to type" meaning that the plants all have the characteristics the original plant was selected for.

Raspberries are in the genus Rubus which is in the rose family (Rosaeceae). Blackberries are also in the genus Rubus but raspberries and blackberries are in different sub-species. There are several species of raspberries, but all together the raspberry species are less complicated genetically than the many species of blackberries. Taxonomists are the people who identify the plants and give them their names. Among taxonomists there are "lumpers" and "splitters;" that is taxonomists who tend to lump related plants in a genus together in a few species, and those who invent new species. The lumpers put common cultivated raspberries together as Rubus idaeus which is the species name for European and Asian raspberries. Splitters hold that the native raspberry of North America is a separate species Rubus strigosus. I lean more to the lumpers in the Rubus idaeus and Rubus strigosus taxonomy debate. But the particular cultivar Bob has was developed in Nova Scotia where the Rubus strigous name is preferred.

Alas, the scientific name isn't really what's important for raspberries, but rather the cultivar name. "Cultivar" has roughly the same meaning as the second sort of hybrid mentioned above: the plants which were selected over time for their characteristics. But in the case of raspberries most of the propagating wasn't done by sowing seeds but division of the actual plants.

The name of the culitvar of raspberry Bob got is "K81-6." What a lousy name! But the cultivar name is important for finding out about the characteristics of the plant. Here's a great page about different raspberry cultivars.

The essential information to know is "K81-6" fruits in late summer on second year old canes. The roots of the raspberry are perennial. From the roots straight canes grow up and these rarely flower. In the second year side growth will emerge from these canes and it's on this side growth where flowers and fruits will emerge. I pruned the canes that Bob took. The task for the plants this year will be to send up the first year canes. So the sad fact is no raspberry fruits on Bob's plants this year. But plenty of fruit next year.

There are some cultivars of raspberries called ever-bearing. These cultivars set fruit in both the early summer and in the fall. What this means is the plant sets fruit on first year canes as well as second year canes. Once raspberry canes fruit, those canes die, or display little vigor. So cutting out the old canes is one of the chores in growing raspberries.

Commercial growers of raspberries usually grow several cultivars to have a long season of production. Generally commercial growers cut the ever-bearing cultivars down to about six inches in the late fall. They do this so the late crop of these cultivars will have a bigger yield. Obviously if the "K81-6" canes were treated like that there would never be any raspberries! Home growers of ever-bearing raspberries often enjoy having both fruiting seasons, so they let their canes over winter. The only problem with this is that pruning is harder when the canes are in leaf. It is good practice to prune the canes which are finished fruiting to keep the perennial roots vigorous and the planting in bounds.

Many home growers have ever-bearing cultivars growing in their gardens. One thing for sure is gardeners are an opinionated lot. Bob will almost certainly get advice about growing raspberries. Much of this advice is sure to be good. But it's essential to understand that the advice to cut the raspberries down in the fall is NOT something he should do with his.

Photo credit: Juhanson from Wikimedia Commons. Photo name "Rubus idaeus." Wikipedia link.

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