Some Plants Go Through Puberty

Considering that it is still pretty darn cold out there, I thought it might be interesting to digress a bit and talk about how some plants go through the “change of life” as they grow up into adult plants.  Here goes nothing!


Anyone who has germinated a bean knows that the first leaves to emerge are what we call “seed leaves” or cotyledons and they bear little resemblance to what comes next, which are the “true leaves”.  The true leaves are what the plant continues to produce for the rest of its life, unless it is programed to have a “vegetative phase change” or what I like to call “floral puberty”.  This topic came up the other day in my office when one of my employees brought in a sprig of a plant that sort of looked like ivy but wasn’t really trailing and even had a “flower” at the end of the shoot.  Never having seen anything quite like this, she was researching it on the internet when I walked in, took one look at it and exclaimed: “that is an adult form of English Ivy”.  I think “too cool” was her response and I had to agree.  


In the case of ivy, it spends most of its life in a juvenile stage as a ground cover or vine.  At some point it “decides” to grow up and become more arboreal.  It changes from a vine to a woody, upright shrub and also starts to flower every year and produce seeds.  While I was growing up in Southern California it was rare to find ivy in an adult form, but for some reason in the northwest ivy matures very early and produces abundant seeds, which the birds then gleefully spread all over the place causing ivy to become a noxious weed in our area.  


Other plants that are common to our gardens also exhibit this “pre-pubescent and post-pubescent” characteristic, but we often miss it.  Many conifers like arborvitae, junipers, spruce, and pines start out with fluffy needle-like foliage and then a few years down the road change to an adult scale-like foliage, or in the case of pines, longer, coarser needles.  I remember as a young boy planting a cute little pine tree with short, soft blue-green needles that had been flocked and decorated for Christmas.  Ten years later I had to remove it because it was 15 feet across and poked my mother every time she came in and out of the house.


If you have ever done flower arranging then you are familiar with the silver dollar eucalyptus that is often used in bouquets.  This is the juvenile stage of this tree and if you planted a young eucalyptus, after a few years it would no longer have round leaves but rather 6 inch long elliptical leaves.  Acacias are also known for doing this, but we don’t generally see them around these parts.  


Several years ago at the Flower and Garden Show I purchased a one gallon Pseudopanax ferox which I subsequently named “Fred”.  He is now 10 feet tall and still in his homely juvenile form of heavily armored, toothed single leaves that are designed to protect him from grazers in his native state of New Zealand.  My goal before I retire is to see him mature like the ones I saw in 2016 when I was in New Zealand.  Wish me luck.