Does Size Matter?

By Jeff Wasielewski

When I go to the nursery to buy a tree to plant in my yard, I remind myself, "David beat Goliath" and "the tortoise beat the hare" . . . and "a small oak, mango, or royal poinciana tree often will beat a larger tree of the same species." That it is advantageous to plant smaller, younger trees as opposed to larger, older trees is a realization that has grown as my knowledge of trees has grown. Over the last three years, I have watched trees planted when they were very small (rootballs 8 to 14" in diameter) outperform and outgrow larger, older, and more expensive trees (rootballs 24 to 36" in diameter) that were planted the very same day.

Unfortunately, many gardeners think bigger is better. Your neighbor who wants an oak tree to shade the back yard will probably go down to the local nursery and buy the biggest, best-looking oak tree affordable - a 15 foot oak in a 32 inch pot. (Obviously, your neighbor has more money to spend on the garden than I do.) The nursery will deliver the tree, dig the hole and plant the tree. And then your neighbor will water the tree and wait . . . and fertilize the tree and wait . . . and wait.

If you take my advice, you'll be imitating the Davids and the tortoises of the plant world. Whether you want an oak tree to shade your backyard, or a mango tree to provide you with fruit, or a poinciana tree to provide a blaze of flowers, you'll buy the smallest, healthiest tree you can find - a vigorously growing tree in an 8" pot. You will carry the tree home in your mini-van . . . dig a hole and plant your oak, or mango, or poinciana . . . water your tree and wait . . . fertilize your tree and wait . . . and then you will watch as your tree readies his sling and stone and outgrows your neighbor's bigger - but not better tree.

So how did your neighbor go wrong? By making the common mistake of thinking bigger is better. That older tree could easily have been in a pot for five years or more, living the effortless life of a nursery plant, with water provided twice daily along with plenty of time-release fertilizer. Its pampered root system took a long time to find water and nutrients on its own. Like many older trees, it had become "root bound" - the main support and storage roots, their growth restricted by the pot, had started to twist and wrap around themselves. When it was planted, much of the tree's energy was expended to repair its distorted roots, energy that would otherwise be used for productive growth.

You will soon find that your small, young tree has several advantages over your neighbor's tree. To start with, a young tree costs less than a large tree. It's also easier to transport and plant. And, most importantly, a young tree has a young and hungry root system - ready to search for water and nutrients and ready to face any challenge. It will develop quickly and naturally, with a root system far superior to that of an older tree planted at the same time. Its sturdy main support and storage roots, never having been restricted by a pot, will grow to anchor the tree, greatly reducing its chances of blowing over in a hurricane. Vigorous, young roots will be ready to gather nutrients from the soil. Consequently, the younger tree will grow faster than the older tree. With all the advantages of a good root system, a younger tree will require less of your care.

So when it's time to buy a mango tree for your garden, don't let those large trees fool you. When it comes to growing healthy, sturdy trees, bigger is never better. Your neighbor, who wants fruit immediately, may buy a large mango tree. However, that large, expensive tree will take longer to fruit than the little tree you buy. You see, the large tree will spend so much time and energy getting established, and repairing its gnarled root system, that it won't have much energy left to put into fruit. Your little tree will become established quickly and will soon be producing sweet, luscious mangos. So remember, for a large, healthy tree, start small. And share those mangos!