And the sites exposure to strong winds. I haven’t noticed how much soil texture affects anchorage… think I will ask CHAT. What I know is that sandy soils encourage much more extensive root systems than clay ones as trees have to reach farther in sandy ones to find the water they need. CHAT’s initial explanation failed to include a very important part of the equation- that irrigated trees in any soil send out fewer roots and tend to not be as well anchored, depending on frequency and depth of the irrigation.
My question to CHAT, “M7 rootstocks for apple trees tend to fall over the first year they carry a heavy crop- that is why they are sometimes anchored to heavy metal conduit when planted. I’m wondering if they are more stable in sandy or clay soils. Sandy soils encourage more extensive roots systems and aren’t as slippery. But the lightness might work against solid anchorage as well as the lack of cohesion.”
ChatGPT said:
Excellent question — and one with a nuanced answer that depends on the soil’s texture, structure, and the morphology of M.7 roots themselves.
Root Architecture of M.7
M.7 has a fibrous, shallow root system with few strong vertical sinkers. It tends to form many laterals in the top 12–18 inches of soil, often poorly lignified in its early years. This makes the stock especially prone to leaning or partial uprooting when fruit load increases before the anchoring wood and roots mature.
Stability in Sandy vs. Clay Soils
1. Sandy soils:
Advantages: They promote deeper root penetration and broader exploration because oxygen availability is high, and mechanical resistance is low. Over time, M.7 roots will extend further horizontally and may develop some modest sinkers.
Disadvantages: Low cohesion between soil particles means the soil doesn’t “grip” the roots as tightly; when heavily irrigated or after rain, the root ball can still pivot under load.
Net effect: Slightly better anchorage over time if the tree is not over-irrigated and if the root system is allowed to spread broadly. But in early years, still quite vulnerable.
2. Clay soils:
Advantages: High cohesion can provide good short-term anchorage even to shallow roots.
Disadvantages: Poor aeration limits deeper rooting, and when wet, clay becomes slippery and offers little resistance to lateral shear. Trees often heave or lean after saturating rain plus wind or heavy fruit.
Net effect: Somewhat more stable the first 2–3 years, but can actually be less stable under fruit load in wet years than in sandy loams.
Best Stability Scenario
M.7 anchors best in moderately sandy loams — soils with both aeration and some cohesion — where roots can extend deeply and laterally without excessive wetness. In very light sands, adding compost or organic matter can help by improving moisture retention and slight cohesion. In clays, mound or ridge planting helps roots stay aerated and better distributed.
Practical Notes
Most commercial growers using M.7 stake for at least 4–5 years, or permanently in windy regions.
Root pruning before planting to encourage lateral branching (instead of circling nursery roots) helps.
Training trees to a more compact form early (light heading, balanced scaffolds) reduces leverage stress.
In short, M.7 is a poor self-supporting rootstock regardless of soil, but well-drained loams or sandy loams will give it the best chance to stabilize over time. In sticky clays, anchorage often worsens once soil moisture fluctuates under crop weight.
I should add that once a tree on M7 has strong scaffolds a single stake driven deep can support the entire tree when attached away from the trunk on one of tis scaffolds. That is if you failed to plant the tree with the stake years before. This is how I anchor larger bare root trees in my nursery that are wobbly after transplanting. Most landscapers waste a lot of time by using 3 stakes and wire wrapped with old hose around the trunks. A single stake taped to a branch with electric tape has always worked for me. Bigger tree- stronger stake, but for my 2.5" caliber, bearing age trees, a single pressure treated 2"by2" 8’ long post works well as can green metal fence posts.
Use a magnifying glass to check trees again in late June. You may want to apply a 2nd oil spray on a relatively cool day if you find scale on your small wood and/or leaves.
For scale doing that much damage, I’d use 2% Purespray at about tight cluster. I’d reduce it to 1% if it needed a 2nd spray in late spring to early summer. Oil tends to suppress scale but not wipe it out and I often have seen damage like that on spring oil sprayed trees.
My M7s are straight-up arrows compared to the M9s… now those guys really want to lean!
About once a year I survey my orchard and any tree leaning I put one of those metal fence posts deep into the ground on the opposite side and crank the tree back upright. If it’s really far over I may need to keep tightening the support over the months. I use chain-lock for all such tree ties now, its really easy to tighten it up a few notches at a time, and you can reuse the stuff year after year.
But M9s are well known to require support throughout their lives. M7 can fool you that it seems well anchored enough for the first several years but then collapses under the weight of its first heavy crop.
My one M7 did not have a heavy crop but it was the first true crop I had on it. I think just the weight and shape of the branching made it tip over…again and again. It was about the 4th or 5th leafing when it decided to do that. Plus we had a very heavy rain the few days prior and it was a wet and rainy week. so the ground was wet but not in an area that puddles water. It was just very wet ground that was saturated and the tree was full canopy of leaves and it was windy. Not a good combination for this rootstock evidently.
I can see that happening with a really heavy crop very easily. Especially with a windy day.
I know it is strange how in some locations or with some people using the M7’s they never have/had an issue with leaning. My one neighbor had fruit trees and and had some apple trees from different nurseries over the years. He had one apple tree that was leaning badly and I asked him if he knew what rootstock it was on. He said he actually kept the paperwork from the nursery he had bought it from. ( he was an engineer and kept really detailed records of everything he did in his house and yard). It took him about a week to get back to me and he said it was on a M7 rootstock. So maybe it is the soil around the area I live in that makes it want to lean. Who knows? I had thought maybe I had not planted it deep enough but the grafting union was only no more than about 1 1/2" above the soil.
I dont have any problems with leaning with my 3 Goldrush on M7 but then they are trellised, happy me.
When i was at the research station we used various means, sometimes experimental, to keep trees standing. The trial plots were spread out over flat farm land with no reprieve from the wind. All the trees we grew, regardless of their rootstock, got support for several years at least.
If conduit was used it was only used when attached to a top wire. 1" conduit by itself would just kink and bend under load.
As far as the economics of it goes, the best individual support was a wooden post, treated of course. If thats not suitable then we did get pretty good luck with the steal T posts. Usually you can just get the 8’ heavy duty ones pounded in 2-3’. @scottfsmith posts above how to use these and with chainlock.
It tends to be more a problem with vigorous varieties which Goldrush is not. However, it should never be a problem if any variety is trained to a trellis.
I don’t think that the pink coloring is scale. I have seen scale on trees and it didn’t look like that. The pink coloring only happens as the apples pass through yellow and become very ripe in my orchard. I never thought of it as a disease. More of an effect. My apples didn’t get as ripe this year, so I hardly saw it at all. We don’t get the heat units that you do back East. We get a lot of chill hours, though.
John S
PDX OR
Ed Laivo feels the same way I do about Gold Rush: best apple tree I have encountered and best all-around apple I know of. Can’t recommend it enough to people who think growing apples has to be hard work.
It is great when and where the season is long enough to properly ripen it. If you are on the short end of the stick it is frustrating that there is not an earlier ripening sport yet. I think that the early one that Adams used to sell is pretty good though- I need to evaluate it for a couple more seasons. I’m also testing Ruby Rush. .
It is frustrating that our season is too short to get the best out of Goldrush, and still it is in my top 10 for bearing reliably, producing edible fruit without much care, and being palatable even when starchy.
If you find a comparable sport of GoldRush let us know. I am just not comfortable putting the GoldRush in my orchard since it ripens really late. I know I mentioned this earlier but since I get below freezing temps in early November I do not believe they will ripen enough to be as great as everyone says they are. I hate to be disappointed in this apple.
Root Architecture of M.7
Stability in Sandy vs. Clay Soils
Advantages: They promote deeper root penetration and broader exploration because oxygen availability is high, and mechanical resistance is low. Over time, M.7 roots will extend further horizontally and may develop some modest sinkers.
Disadvantages: Low cohesion between soil particles means the soil doesn’t “grip” the roots as tightly; when heavily irrigated or after rain, the root ball can still pivot under load.
Net effect: Slightly better anchorage over time if the tree is not over-irrigated and if the root system is allowed to spread broadly. But in early years, still quite vulnerable.
Best Stability Scenario
Practical Notes
