Why Stake Trees After Planting

Q. I just planted a 5-gallon mesquite tree following your advice and was wondering how I should stake it. Also, I was wondering if I should use the deep watering stakes recommended for it? They are plastic, two feet long with holes drilled in it for deep watering and supposed to encourage deep rooting of trees.

A. If the planting hole is dug wide enough, the soil used when planting is amended with something decent, then these deep watering tubes are not necessary. If you water your tree deeply, and not daily, the tree does not need them. If you water your whole yard daily including your trees, which I don’t recommend, then maybe there is some benefit using them. 

Buy Soil Aeration Tubes? 

The problem with digging a planting hole deep when its not needed is making soft soil beneath the tree that may cause it to sink as the soil beneath it collapses and trying to drive a sturdy stake into soft soil and expecting the stake not to move, along with tree roots.

            I have not listened to the sales pitch for these deep watering tubes, but I would guess they are marketed to prevent shallow roots from growing on the soil surface. Most trees don’t want their roots on the soil surface. They want their roots to grow deeply for better anchorage in the soil and access to a larger amount of water. 

The Problem is Soil Aeration

Tree roots need access air as well as water. Roots need to "breathe". Watering so often that deeper soils stay wet or the deeper soil is very compacted will hinder air from getting deep in the soil. True of clay soils, wet soils and compacted soils.

Small trees should have soil amended to a depth of 18 inches, medium height trees to a depth of 24 inches and tall trees, like most of our pines, to 36 inches.

Not all Roots are the Same

Root depth of trees is controlled by three factors; if tree roots normally grow shallow (its genetics which is mostly the soil environment where it is from), condition and type of soil and how the tree is watered. 

These watering tubes focus only on the third factor. 

Control root depth with soil amendments and water management

. Trees and large shrubs should be watered separately from shallow rooted plants like lawns, flowers and vegetables. This gives these larger plants a chance at growing roots deeply.

            Some trees like mulberry and many types of ash have a preponderance of shallow roots. Its normal for them. It is part of their genetics and the environment where they came from. They like floodplains and wet soils. That's why they do so well in lawns. In some cases, these roots can be removed from the soil surface or covered with mulch.

            Some trees grow roots near the surface of the soil where roots can access air better. This happens in heavy clay soils or soils where the planting holes were not dug or prepared well. With heavy clay soils it is best to grow trees on a 12 to 18-inch rise or mound, so the soil can drain, roots can “breathe” and have somewhere to grow.

Advice on Digging Planting Holes

            I have harped on planting holes ad nauseum, but always dig the planting hole at least three times the size of its container and amend this soil with decent compost at the time of planting. Buy these tubes only if needed.

            If the tree is from a 5-gallon container, then it may not need staking. Trees planted from larger containers probably need it. The primary purpose of staking is to keep the roots from moving. Movement of the upper trunk and limbs is a good thing.