Developing some pines for future use

Austrian pine, far right. Standard US 12-oz beverage can for size reference.

I picked up these trees yesterday: a baker's dozen of ponderosa pines (Pinus ponderosa) and one Austrian pine (Pinus nigra.) All are young trees, probably two to three years old: young enough for what I have in mind. All of them were on clearance at a local garden center; the manager was happy enough to have these trees off his hands that he sold them to me for 75% of the clearance price (40% of the original price.)

A number of them have needles that are browning toward the tips; but that's not unusual here in young pines that have sat in a garden center all season, often overwatered. All 14 have fat, healthy buds for next spring, so I'm not worried about them. All 14 will have no problem overwintering with my hardy trees; their species are fully cold-hardy here.

Tucked in under the Rack with the other hardy trees.

I bought these trees aiming to develop them into good raw material for bonsai. (That's why I wanted them young and small: so there will be less to correct.) Northern Indiana simply has no good sources of raw material for non-tropical bonsai. The closest bonsai nurseries are all more than 100 miles away. One must buy bonsai stock on-line, or else shop in a general-purpose nursery. Good bonsai candidates can be found in general-purpose nurseries, but one has to know what to look for. Even then, one good find in 100 nursery visits is about the best average success rate that can be expected, in my experience.

1-gal. Rootmaker®. 7 inches on each side at top.

Inside closeup of Rootmaker®. Click to enlarge.

In spring, each of these trees will be repotted into a 1-gallon Rootmaker ® growing pot. The Rootmaker®  is designed to promote the development of a compact fibrous-root system, close to the trunk. Let me describe briefly how it does that.

In a typical round nursery pot, the roots grow outward until they hit the sides of the pot; then they grow down to the bottom, where they circle round and round. Fibrous feeder roots are usually found only near the ends of the long circling roots.

In a Rootmaker®, the roots grow out until they encounter the sides of the pot, then start down, just as in a standard pot. But the sides of the Rootmaker® are designed with rows of shallow triangular steps (green arrows in the picture.) The edges of each step are designed to create a little channel on each side, along the inside of the pot wall (yellow arrows.) Those channels guide the root tips to holes in the sides of the pot (blue arrows,) where they emerge into the air, dry and die. The plant seals off the dead tips, keeping out pathogens, and the roots respond by branching further back, where they're still inside the soil mix. The end result is a well-branched, compact root system close to the base of the tree.

I've been using Rootmakers® for a number of years now. They don't work well with exceptionally vigorous growers, like willows and Ficus: the roots grow so fast that they quickly block the air-pruning holes. Otherwise, I have found these pots to work as they are meant to, and I am happy to recommend them. My Rootmakers® are an older model, but the company is still in business. You can learn more at www.rootmaker.com.

Each of these pines will spend at least two years in a Rootmaker®, then be moved up to a larger growing pot. Most of them will be shaped enough to put some movement into their trunks. They'll be fertilized regularly, and pruned and pinched in such a way as to encourage low, compact branching. If all goes as hoped, in three to five years each one will be a nice piece of bonsai raw material, ready to be styled or grown on further, as a new owner may decide. I plan to offer them for sale when they're ready, starting with local bonsai practitioners.

That's the plan, anyway. I expect to learn new things along the way. Check back in a few years!