Monday, March 3, 2008

Earth Day Seedlings


We often give away seedling plants for Earth Day and this year we will be giving out seedlings of Southern Magnolia (Magnolia grandiflora). Take a look at how our seedlings are germinating. We collected the seed off our collection of the hardiest known magnolias last November and cold stratified the seed this winter.


Look closely and you will see a gnat on the left seed coat. The seed is germinated in an open flat in the Greenhouse.

The new seedling sheds its seed coat to reveal its two seed leaves called cotyledons (plants with two cotyledons are called Dicotyledons or Dicots for short). Magnolias are some of the most ancient of Dicots, which are the flowering plants.


The new seed leaves do have chlorophyll and begin photosynthesis to harvest the energy of the sun. All life on Earth could not exist without this process. In the coming weeks we will transplant these seedlings into individual containers for you to take home on Earth Day. (Quantities will be limited--so come early!)

We chose to give away Southern Magnolias for Earth Day because it is an ancient species that has withstood climate changes beyond our comprehension. There are 17 million-year-old fossils that key to this species! When Europeans settled North America they were native to only the Coastal Plain of the United States from southeastern North Carolina south and westward to eastern Texas. A long time ago they were native in what is now Missouri and are actually expanding their range northward again, aided by cultivation and milder winters. We have actually had seedlings emerge and grow beneath plantings at Powell Gardens.


Here is what your seedlings will look like in a few years! It takes five years for them to achieve this size. The first of these seedlings (on the south side of the hort cabin) bloomed last summer but usually it takes a seedling eight years to flower. The flowers are the classic huge white bloom of intense fragrance. Southern Magnolias bloom in late May and early June and sporadically through summer and occasionally into fall. Their late-blooming nature allowed them to escape the Easter freeze last year. They should be planted in a sheltered place because they do not like temperatures below 0F but our selections should survive -15F and have survived a quick dip to -25F (with all the leaves killed). They are extremely heat and drought tolerant.


Southern Magnolias become huge evergreen trees to over 100 feet in height in the Deep South. In Kansas City the champion tree is about 45 feet tall with an equal spread. They usually reach about 30 feet in our area and are not recommended north of here. Each flower lasts only three days but they are produced sporadically over a long period. They make great cut flowers to enjoy in a rose bowl. The fruit in fall looks like a popsicle and red-coated seeds emerge as this cone-like fruit ripens. Mockingbirds relish the fruit but they are quite beautiful to our eye against the lustrous, evergreen leaves. Stay tuned for more about Earth Day at Powell Gardens.


All photos taken by Alan Branhagen on March 3, 2008.

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