How much chemical use is normal in nurseries?

For better or worse, the use of chemicals has become widespread in all agricultural production, including nurseries. In our operation, we try to minimize the unnecessary use of chemicals wherever possible. With our soil type, we are able to use very small quantities of fertilizer. On our entire 190 acre operation we use less than 160 pounds of fertilizer per acre per year. Compared with a typical containerized nursery that uses up to 1700 pounds of fertilizer per acre per year, this is very low. As a comparison, a properly maintained home or landscape lawn could easily receive 1600 pounds of fertilizer per acre per year.

As far as pesticide use is concerned, we make the best possible use of environment friendly products such as Dormant Oil. We also monitor our various cultivars and species and only spray where and when necessary. Unfortunately, economics dictates that we grow cultivars in consolidated blocks and this does lead to more insect and disease problems than are encountered in the landscape. We make extensive use of various grass species for in between our tree rows, minimizing the need for herbicides. We use these down the actual tree row and generally make applications at half the recommended label rate.

What problems do you have growing the same species on the same ground, year after year?

We try hard to avoid this situation by carefully rotating our production. By utilizing past crop plans and maps, it is possible to avoid planting the same species back into a piece of ground for many years. We also avoid planting certain species into areas that would naturally cause them problems. e.g. Japanese Maples into poorly drained areas.

Do you 'top' your trees?

Yes and no! Rightly so, there is a strong movement against topping trees in the landscape. Topping of trees in this fashion has a severely detrimental effect on both the appearance and physical well being of the tree. The situation in the nursery is very different to the situation in the landscape.

Firstly, the reasons for pruning nursery trees:

• to promote adequate side branching to provide for a balanced and full head.
• to prevent excessive length of growth that would result in a poorly shaped tree.

The way we achieve this is by tipping the leader to a strong bud and then taping this bud so that it grows straight. This is only done into one year old wood, unlike landscape topping that is usually into much older wood. New wood has active buds with strong connections to the parent branch. Older wood will usually only produce adventious or water shoots that are weakly attached to the originating branch. Tipping of side branches is also an annual procedure with young trees but, in this case, they are not taped as the desire is to promote a balanced, evenly divided branch structure. Our pruning program has been developed over a 20 year period and has been reviewed annually by a team of experienced professionals for the effect of each pruning cut. All the cuts that are done are carefully considered cuts with the object being to direct the new growth into the desired position. This is not indescriminate "hedging" or "rounding". By not tipping, the result with most species is to produce long, unbranched limbs, that are weighed down by their own leaves and/or spring rains. These then open the structure of the tree leaving it extremely unattractive to most people.

Why do you stake your trees…doesn't this make them weaker?

We only stake certain species of trees, for example, oaks. The reason for this is that, as young trees, they have inherently weak, rubbery wood. With the amount of growth we regularly get in the nursery, this can cause the main leader, or even the whole tree, to bend over. This makes the tree unsaleable. When we stake, we use either bamboo or steel stakes. As these have a measure of flexibility, they allow the tree trunk to move and sway thus promoting eventual strength. A tree grown in this manner will have a strong, straight trunk which will provide it with strength and longevity.

Don't you lose most of the root system when you dig your trees?

We have seen some very high figures quoted for root loss resulting from Ball and Burlap digging. We work very hard to minimize both the root loss and the effect of it on the tree. Firstly, we start our trees with liners that have been root pruned up to three times. We then root prune them again before planting. We utilize drip irrigation which, when coupled with our soil, produces a finely structured, compact root system. The drip irrigation along the tree row and the grass in the middle of the row produces a distinct zone in the row which is more conducive to root proliferation. When many of our trees are dug, the size of the roots being cut is smaller than 1/2". Roots this size produce new root hairs soon after digging and can begin the re-establishment process.

What determines the branching height of your trees?

Basically, the marketplace. In some cases, the growth habit of the tree will also dictate what is the best height, but generally we try to grow our trees they way most people want them. Inevitably, this means we grow the way some other people don't like them. Like democracy, we tend to go with the majority, however, if a new branch height or growing system is mentioned to us, we will always take a look at it. The best way to ensure that the trees that end up on your project meet your expectations is to specify these kind of criteria in the bid specifications. Then, if the trees are not commonly grown that way, you have time to make arrangements for special pruning or growing on contract.

How do you store your trees during summer?

Generally, we wrap the rootballs with shrink wrap and stand them upright in a protective mulch with drip irrigation applied directly to the rootball. The shrink wrap is to prevent excessive root growth out into the mulch and encourage root development within the ball. This also prevents shock to the tree when it is pulled during the summer months as the new root growth is not disturbed nearly as much.

How does summer digging compare with stored trees?

In the humid areas of the country, summer digging can be very successful with a wide range of species. Here in the West where our summers tend to be much less humid, our options are severely limited. Summer digging carries with it some risk...period. Some nurseries will tell you no problem, but the risk is there. Careful and special handling techniques can reduce these risks with some species but it does not eliminate them. Stored trees have been dug during their normal period of dormancy and have leafed out in an appropriate way to compensate for any transplant shock. Conversely, summer dug trees have been growing in the ground with the benefit of an undisturbed root system and have produced the amount of foliage in anticipation of retaining all their roots. Suddenly, the unsuspecting tree is weaned with little warning and exposed to hot dry summer conditions and often, freshly sealed asphalt in parking lots. Which tree would you prefer to be?

This is not to say that summer digging cannot be done, it can, but it is not as easy and risk-free as some would like to believe.

Do you have problems with graft incompatibility?

With some species, graft incompatibility can be a problem. In these cases, the industry looks for alternative ways to propagate these species. One good example is Acer rubrum. When cultivars are grafted onto seedling rootstock, there used to be many problems with incompatibility. Eventually, a successful way to grow these cultivars on their own roots was found and the problem solved.

What is the most common problem with tree survival after transplanting?

By far the most common cause of tree failure after spring transplanting is lack of water. Most people do not appreciate either how much water a large tree can use during hot weather, or how easy it is for the rootball to dry out in a matter of hours. Superficial watering will achieve little. The rootball needs to be thoroughly wet through and this can take many gallons of water. Immediately after transplanting, the only water available to the tree is contained within the rootball, so the best method of watering is to inject the ball or apply drip irrigation directly on top of it. If the tree was left lying on hot asphalt prior to being planted, then up uphill struggle will ensue.

The second most common cause of problems is the antithesis of the above. Naturally poor drainage or bad planting technique causing artificially poor drainage. Either of these can cause leaf yellowing and drop in certain species. Unfortunately, it is often interpreted as lack of water and irrigation is increased.