Sunday, June 5, 2011

Winter rhizome maintenance and pruning

Sarracenia produce all their new growth from a modified stem called a rhizome. Although rhizomes may not immediately look like a stem, they have all the characteristics of one - a growing tip or bud and secondary growth points or nodes that develop all the way along the stem. Depending on where the nodes are, and what the plant needs, they may produce either roots or new growing points. Because all growth comes from the rhizome, they need to be carefully maintained for full growth. The best time to do this is winter, when your plant is dormant and new growth can not be damaged.

Here is a photo essay of maintenance I perform on all my plants during winter.
Sarracenica flava var rugellii before being cleaned up for next spring.

Our model today is a Sarracenia flava var. rugellii I call the rammeting clone, because it produces new clones of itself, or ramets, by division very readily (see also Carnivorous Plants of the United States and Canada by Don Schnell). Here we see the plant as it was in early winter 2011.

Note the dead, woody bases of the past season's leaves.

Taking a close look at the plant, we can see that the rhizome of this plant is cloaked with the old growth of past seasons. This is a problem, because it tends to harbour pests and keeps nodes from producing new growing points.

A gentle pull and they are gone!
Fortunately, these old leaves are easily removed - simply give them a gentle tug backwards and downwards. This peels the old growth off, exposing the rhizome to light and triggering new growth.

Dead growth removed from the rhizome.
This is what the dead growth looks like when removed.

And this is a graphic demonstration of what can be hiding in the dense growth of spent leaves - mealybugs. The fluffy material around the nearly mature mealybug is an egg mass, covered in the waxy secretions that give mealybugs their pale colour.

Looking closer again, we can see that there are not just eggs - there are also newly emerging mealybugs called crawlers. They are the pink-coloured pill-shaped things around the nearly mature mealybug. Crawlers are designed soley for spreading to other plants. The ones in the rhizome are more or less limited to this plant - they are hard pushed to move 40 cm on foliage. But any crawlers higher up on the plant can drop into the air and be carried to another plant. This may seem like science fiction, but mealybug crawlers fall at only 42 cm per second - 1.5 kilometers per hour - which means any wind moving faster than this can potentially keep them aloft.

A nice and clean rhizome after having old seasons stems plucked off.
Once you are done, your plant should look like this - a nice clean rhizome. There are plenty of spots for new growth on this rhizome.

You should also have a pile of plucked leaf bases.

A festy rhizome! Note the clean area in the middle - this would be more likely to shoot fresh growth than the mossy areas.
This is an example of a dirty rhizome, with moss and soil covering nodes where shoots might otherwise grow. Mosses covering the rhizome like this should also be gently removed during winter dormancy. Exposing the rhizome to light favours the production of new growing points (and ultimately more plants).

Pruning off last season's growth - make sure you use a sharp, clean pair of secateurs.
Once you are done with the rhizome, move on to the rest of the plant. Trim off all dying leaves, leaving enough for them to photosynthesise and that you can easily remove them next year.

Trimmed and ready to grow another year.
I like to trim the leaves of my plants to the same height for neatness.

At the end of all this, you will have a happy plant, ready to grow well through another season.