Saturday, July 28, 2018

Odds 'N Ends - Experience with Bare-Rooted Tree Seedlings

The economical way to have shrubs and trees in quantity is to start with bare-rooted seedlings that we here in the Midwest can order from our state conservation departments for less than a dollar each.  However, seedlings require a lot of TLC until they become established during the first growing season.  For what it's worth, I would like to share our experience with them on two occasions.

Reminder:  click on any photo to enlarge it for better viewing.

Current Project
Last fall, we placed an order with the state conservation
department for 80 bare-rooted seedlings to be delivered in the first week of April.  I thought that we would be finished with the dirt work behind the house by early spring and could start a woods behind the house using species of hardwood trees that are recommended by Doug Tallamy in his quintessential book on native landscaping as being the  most beneficial to wildlife.  "Wildlife" not only means the kind with four legs or two wings but also, and perhaps more importantly, a host of insects like pollinators that depend on trees for part of their life cycles.

By the time I finished the final grading behind the house, the exposed soil in many areas was hardpan (glacial till) through which tree roots do not penetrate and the thin layer of topsoil that I deposited would support at best only shallow-rooted nuisance grasses like crabgrass. The bare-rooted seedings would have to be planted somewhere else.  Fortunately, the acre lot on which we live next door to the construction site combined with that part of the building site that could support trees would provide ample spacing for the seedlings.

Temporary "Planting"
The delay between arrival and planting of the seedlings required that they be temporarily "planted" to keep the roots happy.   Dorothy and a friend dug shallow trenches in Dottie's fenced garden, laid the plants on the ground with their roots in the trenches and covered the roots with a shallow layer of soil, a maneuver called "heeling in".  After watering the protective soil, they covered it with cardboard and old carpet to hold in the moisture.  Then as needed, Dottie kept the plants watered until ready for planting.  However, holding them in this fashion for two months does not bode well for success; more of the seedlings did not survive than would have been the case if they had gone into the ground either when received or shortly after.  Mostly it was nearly ten of the black oaks that suffered due to spindly root structure compared to the other varieties -- white oak, burr oak, shumac oak, pin oak, hackberry and black cherry.

 Planting the Seedlings
Nothing needs to be said about digging a hole big enough for root cluster and refilling it while holding plant in the correct position to have the root-trunk junction at the right level.  I would mention, though, that for easy digging, I used a clam-type posthole digger then, for the tree seedlings having tap roots, such as the oaks and black cherry, I used a soil auger in a cordless drill to deepen the center part of the hole.  I made no attempt to amend the soil beyond using only topsoil for backfilling.

Ideally, the trees should be planted randomly so as to mimic a natural forest.  But, in order to make mowing with a lawn tractor easier, I held my nose and planted them in a grid pattern, allowing about 20' between trees.

Protecting the Seedlings from Critters
The topography here in the Mississippi River bluffs is sufficiently rough to provide numerous timbered gullies that are rugged enough to stay undeveloped.  As a result, our town supports a lot of closeup and personal wildlife.  A friend gave us some oak seedlings last summer that we planted without protecting immediately.  Within a day or two they had been eaten, probably by deer but maybe rabbits.  This time we didn't let the the seedlings go unprotected even for one night.

A quick Google search reveals myriad choices for cylinders in which to grow trees until they become established, usually called "grow tubes".  They range from solid plastic tubes with various hues to tubes that are like stiff netting.  Most are supported by small diameter bamboo sticks that are pushed into the soil.  We chose the netting type seedling protection tubes that are used with reforesting after clear-cuts in northwest USA because they are much cheaper than the "mini-greenhouses" that the solid variety comprise.  Mating the netting with the bamboo stick was a simple matter of of weaving the bamboo through the netting in a few places.

Initially, we used mulch around the seedlings to hold moisture and to keep grass at bay.  In order to do the latter effectively, though, the mulch area would have to be substantial.  Instead, we opted for a small amount of mulch initially to cover the soil that was denuded during planting with the intention of letting the grass grow up to the seedling eventually -- kinda.

Protecting the Seedlings from Mowing
If grass encroaches on the seedling, how do you mow it? 
4" PVC pipe +/-8" long cut
 partway through on one
side and completely through
 on the other
 Before placing the grow tube over a seedling, we slipped a 8" section of 4" PVC pipe that had been modified for easy removal (next paragraph) when the tree trunk got too big for the pipe.  Then we slipped the grow tube part-way over the pipe then forced the bamboo into the ground.  The bamboo supports both the pipe and the grow tube.

In order to facilitate removal of the pipes, they were run through the table saw twice.  For the cut on one side, the blade was adjusted so as to cut only about two thirds of the way through the wall thickness.  The second cut on the other side went completely through the wall of the pipe.  At the time of removal, it will be a simple matter of using a flat tool to pry the cut side of the pipe apart until the partially-cut side breaks apart.

In the meantime, I will be able to string-trim the grass
A drip hole of 1/16" drains the
2.5 gal container in +/-2 hours
up to the pipe without damaging the grow tube or the seeding.  Eventually, after removal of the tubes and pipes, mulching out a ways from the trees in a more typical manner will be necessary until the trees grow into a proper woodland whereby the shade, leaf litter and forest-specific undergrowth will eliminate mowing. 

Drip Irrigation During the First Season
The closest thing we have had to a genuine drought was in 2012, the year we raised about 60 bare-rooted seedlings in anticipation of having them reach a transplantable age by the time we needed them for landscaping around the new house.  Lo, six years later when we are finally at the landscaping stage, the seedlings were way past transplanting.  However, despite the drought that year, all but a handful of seedlings survived thanks to the drip irrigation system that was suggested by the farmer in our family who also provided the containers for it.  And, in retrospect, our success was also due to growing them only a few feet apart in an enclosure
that kept the deer at bay for a couple of years until large enough for the deer to reach them over the fence.  By that time though, a little pruning did not matter.

Any decent-sized container -- round, square, rectangular -- can be modified for drip irrigation.  The 2 1/2 gallon containers we obtained from brother-in-law, Ron, originally held a surfectant that is used to enhance the effectiveness of sprayed weed killers.  Thorough rinsing with tap water is all that is needed to make them safe for watering plants.  By trial and error, I found that a 1/16" diameter drip hole as close to the bottom as possible will mean that the container will drain in about two hours.  Rather than hassling with the lids for the containers at each fill-up, we left them off.  Some debris does find its way through the opening, mostly grass clippings from mowing nearby, but it is largely flushed out by overfilling the container with water each time.

As ballast against the wind, I add enough pea
Pea gravel after washing; a quart in each container is
ballast enough against most winds and keeps mosquitoes
 from breeding in any water standing after draining 
gravel to each container to cover the bottom -- about a quart for our containers.  In addition to keeping the containers anchored, the gravel covers any water still standing after the drip stops, making it inaccessible to mosquitoes.  And, being a bit anal, I try to position the containers on the north side of the seedling so as not to block the sun.

While filling a container with water, it is a good idea visually to check the drip hole to be sure it is flowing freely.  I carry a 4d finish nail for reaming any sluggish holes.  Also, during dry spells, I jump-start the watering by filling the PVC pipes with water either before or after filling the containers.  It slowly leaks out through the sawcut but the soil around the plant is nevertheless thoroughly saturated.

At the end of the growing season, it is advisable to be sure the containers are dry and stored where they cannot collect water that could freeze and burst a container.  When reusing the containers, it is best from the standpoint of preventing clogged
drip holes to empty the gravel into a wash tub or some other large vessel filled with water.  Then, stir the gravel until vegetative debris floats to the surface and goes away when the water is poured off.  Rinse the containers clean, add back the gravel, prophylacticly ream the drip holes and
start watering.
Seedlings planted between new house and our residence

The nearby photo shows the configuration of the protective PVC pipe, the protective grow tube with a bamboo support stick and the drip irrigation container.  Notice that the container is tilted away from the plant, which is not always avoidable, meaning that the container will not drain entirely. The layer of pea gravel in the bottom covers any standing water sufficiently that mosquitoes cannot breed in it.  The black cherry seedling is already growing through the tube netting but, our experience is that deer browse will not harm the tree at this early stage as long as there is plenty of growth within the tube.  

A garden hose works best for filling the containers either directly from a silcock or indirectly from a mobile tank.  Since most of our seedlings cannot be reached with a hose from the house, we temporarily re-purposed our rain barrel for this job. It has a hose bib at the bottom for a garden hose and a hole on top for filling.  When lashed to my truck bed, there is enough gravity flow to fill a container in just a few minutes.
Seedlings on our residence property; beginning in August, apple-loving
deer are regular visitors at dusk and through the night eating directly
off of the trees in the background and picking up fallen apples

*  *  *  *  *       
Several of the grow tubes and PVC pipes have been "vandalized with the bamboo poles broken off at the ground and the netting and PVC pipes strewn across the lawn as well as few leaves left on the seedlings.  About a dozen seedlings were bothered.  Our vintage apple trees are magnets for deer; deer congregate starting even before dusk and can be seen all night.  Undoubtedly the damage to the seedlings was deer-centric, probably by bucks trying out their new antlers and finding tasty snacks in the process.  Based on the severity of the damage, I am not sure that sturdier tubes and support poles would withstand the abuse any better than the netting and bamboo.

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