Monday, February 9, 2015

Checking the Draba and Leavenworthia

I gave the barrens a close examination and found the winter annuals to be doing extremely well this year.  This Leavenworthia uniflora rosette has a healthy cluster of leaves and at least four flower buds nestled in the center of the whorl.  That’s quite an improvement over what I found last year.  The difference is the result of nearly no snow cover this winter, while snow covered the ground most of the winter last year.  Leavenworthia germinates in the fall and grows throughout the winter.  Snow cover blocks the sunlight and slows the growth of the plant.  After an especially snowy winter, both plant numbers and size are decreased.

This is where the Leavenworthia grows.  It sinks its long tap root as best it can into gravelly limestone soil.  A well anchored root is essential to survive in a soil that alternately freezes and thaws through the winter.  As the soil freezes, it expands and pushes upward.  Plants not anchored to the soil below the freeze line are pushed up and left stranded on the surface when the soil thaws and falls back into place.

Plants that survive the rough winter conditions will flower in the spring.  Seed will mature before the poor soil dries out in the summer sun.

Draba cuneifolia has a life cycle like that of the Leavenworthia.  Its small rosette of leaves is working hard to turn sunlight into energy for that all important process of producing seed for next year’s population.  At this stage, the tiny plants are almost impossible for a person to see from a standing position.  It’s necessary to get your eyes close to the ground to find these plants.  The cedar needles and dried grass stalks are an indicator of the plant’s diminutive size.

The Drabas are also quite numerous this year.  With luck, there should be a tremendous amount of seed produced.

Still, the plants growing in the barrens don’t come close to matching the tremendous growth displayed by my container bound population.

The Drabas are so crowded together in the container that other plants have trouble competing.  The small pointy leaved plants are Chickweeds that are having trouble breaking through to the sunlight.

Where the Drabas are not so crowded together, the individual plants have attained a larger size.  In these areas, Leavenworthia is able to find room to grow.

The Leavenworthia is having trouble maintaining itself in the container dominated by Draba.  I have already prepared a new container that will be solely dedicated to Leavenworthia.  When I originally put these two species together, I was expecting them to behave as they do in the barrens and just produce a scattering of plants.  It’s obvious now that I was mistaken.  I’ve been growing these plants in containers for several years and seem to learn something new about their growth habits every year.


  1. I always love these posts. I know who to seek out when I need some rare mustard seeds :)

  2. Hi, Andrew. These plants are a couple of my favorite species. Of course, there are several dozen more that are also my favorites, so that designation encompasses a fairly large group.