Autumn Orchard Care

Aside from harvesting the fruits of your spring and summer tree care labours, what should you do for your fruit trees in the fall?

Autumn is a great time to mow, mulch, and add critter protection to make sure that the mice, voles, rabbits, and deer don’t eat away your trees when food is scarce in the winter! Let’s walk through some tips and tricks of autumn tree care so that you can set yourself up for many plentiful harvests to come.

Here’s my little “MMMunch” mental checklist for fall tree care:

• Mowing
• Mulching
• Critter Protection

“MMMunch” – the first two m’s are for mowing and mulching! Then you have munching which is what you want the tree’s roots to do and what you don’t want the critters to do!

Mowing

Mowing will make it easier for you to work around your trees and you can save your grass clippings to use as part of your mulch. Depending on where your trees are and how you care for them throughout the season, this step may look different for each of you. If you’re like us and have left mowing to a minimum all season, you’ll appreciate the ease and added visibility provided by mowing around your tree before trying to lay down mulch.

In an older and more established orchard, you may need to crouch under the tree canopies and may find it easiest to use a push mower or carefully weed whack around the trunks. You can also remove grass and debris around the trunk by hand. Removing large tufts of grass from directly beside the trunk removes the homey spots where voles and mice as well as ants and other insects that could damage the trunk might make homes.

It’s good practice to do this for your trees at least biannually, generally once at the first cut of hay (usually around late May, although it varies year to year!) and then later in the fall before winter arrives. 

Mulching

Once mown, your trees are ready to be mulched. Fruit trees are heavy feeders – they put in a lot of effort growing fruit every season and thus they benefit from extra support in comparison to an ornamental tree. Mulching can be done in both fall and spring. 

What are the goals of mulching? 

• Provide organic materials and nutrients to the soil and thus also to the tree’s feeder roots. Feeder roots that spread just under the surface of the soil all the way out to the drip line (where the tree canopy ends).
• Retain moisture in the soil.
• Regulate the soil temperature (warmer in winter, cooler in summer).
• Suppress weeds for a little while as the mulch breaks down.
• Attract beneficial insect buddies and/or repel various insect pests.
• Improve the tree’s immune system through better soil health and biology.
  

What should you mulch fruit trees with?

Organic materials such as wood chips and bark mixed with compost or well-aged (rotted) manure make good mulch for trees. Straw and hay can also be used effectively. All of these options can be mixed and matched based on your needs and what is readily available to you. In most cases, you’ll likely want to do multi-layered or mixed component mulching for the best tree-feeding. To help you decide what works best for you, let’s look at the qualities of various mulch options and then how to apply it around your tree! 

Woodchips and Bark Mulches

Woodchips and bark mulches are among the most common mulching materials, but it is worth knowing about the qualities below to help you choose a good wood-based mulch:

• Lower in nutrients compared to compost.
• Long-lasting with good moisture retention and soil insulation.
• Hardwood chips are most beneficial to soil fungi & are great for trees that like neutral or alkaline soil.*
• Pine bark mulch may make the soil more acidic but pine mulches are mostly neutral by the time they make it to your trees. Fresh pine needles are mainly the cause of changes in soil acidity.*
• Cedar mulch has insect repellant qualities from its natural cedar oil and this can repel termites and certain types of ants.
• Coloured mulches (dyed red, orange, or black) are not recommended because the dyes may be toxic to the tree once leached into the soil.
• Fresh woodchips work, but aged woodchips may be better.**

*If you’re sourcing free woodchips from tree-care services or townships, you likely won’t have any control over what wood sources your chips are from. However, they also will be more likely to include bits of leaves and small, young branches which will add nutrition to the mixture. Unless you have very specific needs for acidic or alkaline soil, most free woodchips can be used without stressing out about your soil pH and can be a wonderful option for feeding your trees.

**The organisms and soil bacteria that break down fresh woodchips need nitrogen to survive. Because woodchips are low in nitrogen the organisms pull it from the soil, temporarily depleting the soil around the tree of nitrogen. As heavy feeders, the loss of nitrogen can be hard on older trees and is particularly hard on young trees. Thus, allowing your woodchips to age in a pile for awhile (1 year or so) may be better than applying fresh woodchips. You can also mitigate this by using compost as a first layer.

Compost & Well-Aged (Rotted) Manures*

Adding at least a little nutrition of some kind to your mulch layers is recommended. Both composts and aged manures offer this:

• Rich in nutrients (nitrogen, phosphorus, & potassium) and organic matter that will be added to the soil over the next weeks and months = good soil feeder!
• Require more frequent replenishment than woodchips.
• Can be applied in layers of 1 or 2” underneath woodchips or other mulches.

*Note that manure should be well-aged (rotted) because fresh manure can burn the tree roots. Any manure you get from a garden center will already be aged, so this is most noteworthy if you farm or have access to fresh manure from a farm. 

Leaf Mulches (Leaf Mold)

It's easy to make your own leaf mulch (also called leaf mold after aging) yourself, and can be used both layered with other mulches or on it's own. Leaf mold is:

• A nutrient rich option that is similar to compost.
• It’s easy to make:
  • collect leaves - optional: shred with a mower to speed up decomposition, avoid oak leaves, which take longer to decompose
  • pile the leaves, spray with water, & cover with a tarp
  • age 1-2 years: allow them to decompose via the actions of fungi and other organisms for up to two years
    
• leaves on their own can be used to create a mulch layer (shredded or whole) without aged decomposition - they'll just take a bit longer to begin feeding the tree, and freshly fallen leaves will not temporarily deplete the soil of nitrogen.

Straw and Hay

In most cases, straw and hay will work best combined and layered with other mulches.

• Lighter and decompose more quickly compared to woodchips.
• Good insulation for mild winters.
• May attract rodents such as mice/voles, so consider this before using heavily.
• If the straw is full of seeds you may end up with more weeds than you expected.
  

Ramial & Willow Mulches

Ramial means “related to branches”. In this scenario it refers to the youngest (under 3cm diameter) branches removed from trees during pruning. These branches can be chipped and used as a mulch that is richer in nutrients than regular woodchips because there is a higher ratio of cambium (living tissue) in the young branches than there is in older branches which contain more heartwood.

• Ramial mulch can be made yourself using pruned (non-diseased) branches from dormant and summer pruning sessions.
• Willow mulch can be made the same way as ramial mulch, with cuttings from a willow tree. This adds salicylic acid, which can improve your trees’ immunity towards common fruit tree pests and diseases.
• These mulches may still cause nitrogen to be depleted in the soil during their first year decomposing, so it’s still a good idea to either add some compost along with them or age them for a year before using under your trees.
  

Wool (Raw or Mats)

Relatively new to the scene (at least with regards to popular mulches), here's what you should consider about using wool for mulching:

• Provides good weed suppression which can be long lasting (1-2 years).
• Good moisture retention & insulation.
• Likely not best option for acid-loving plants since it increases soil alkalinity.
• Can be used with additional mulch layers to hold the wool in place and add other nutrients.
• Raw wool can be a bit odorous as it breaks down.
• Using mats is best for younger trees (1-4 years) as they are generally sized to fit around smaller trunks.
• Sourcing wool mats or raw wool could be a bit expensive.

Hemp Mats

Currently, hemp mats are one of our go-to options for placing around newly planted young trees, and we stock them as planting supply hard-good in our store. 

• Provide good weed suppression (1 year).
• Good moisture retention and insulation.
• Best for younger trees (1-4 years) as they are sized to fit around smaller trunks.
• Can be used with additional mulch layers to hold the mats in place and add other nutrients.
• A bit more cost effective as hemp mats have been on the market longer than wool mats.

Paper Product Mulches

A wet application of paper products can provide a DIY weed suppression:

• Use paper products such as wet newspaper (layered 2-3 sheets thick), wet cardboard, and/or shredded paper (wet down after spreading).
• Paper products will not deplete soil nitrogen like fresh woodchips do.
• Paper products do not add many nutrients to the soil so you can apply some compost below them if needed, followed by other mulch layers over top.
  

How should you apply the mulch?

Mulch can be applied thickly (around 4”) or if your tree is doing splendidly and doesn’t appear to need much (or you’re budgeting a limited amount of mulch around lots of trees), you can apply a thinner 2” layer. Extend your layer all the way out to the dripline of the tree. If layering several types of mulch, keep in mind their qualities as outlined above (i.e. compost, then fresh woodchips, etc.) Keep in mind that applying too much mulch (6”  or more) can create a heavy layer that deprives the underlying area and tree roots of oxygen, which can cause other issues.

The real key in mulch application is that you absolutely do NOT want to heap it against the trunk of the tree! 

Why? Because when heaped against the tree trunk, mulch can contribute to the following problems:

• Creates a home for ants, mice, or other beings that can damage the trunk.
• Adds moisture and can contribute to collar rot (rotting around the base of the trunk).
• For a young, grafted tree, heaped mulch may cause the tree to root out above the graft union which would cause you to lose the benefits of your rootstock such as dwarfed growth*

*This is a specific circumstance that would only happen if the mulch was heaped high enough to be above the graft and if the tree is young enough to want to root out rather than rotting, which is more likely with an older tree.

So how can you avoid these issues? Picture a donut or volcano shape around your tree trunk:

• Pull the mulch back so that there is little to no mulch for the first 4-6” out from the trunk.
• Allow it to heap up to your 4” mulch height around the tree, creating a donut-y or volcano-y shape (more visible with a young tree that has a small diameter to the drip-line).

The roots you want to feed are located out under the canopy, so keeping the mulch 4-6" away from the trunk also ensures you’re feeding the correct area and not wasting the tree’s food!

Munching: Critter Protection

Deer, rabbits, mice, and voles seem to be the biggest winter tree predators for my dad’s farm (True Root Tree Co.) and for us here at Silver Creek Nursery. Regularly visiting and looking closely at your fruit trees is a key component of good tree care, but there are also several things you can put in place during the fall or plan into your orchard set-up/maintenance to help mitigate winter critter damage:

• spiral guards
• bait stations
• deer fencing
• DIY protection barriers
  

Spiral Guards

These are our go-to method of protecting the trunks of young, tender fruit trees that are in their first 5-6 years of growing. These guards help to prevent rabbits, mice, and voles from chewing away the bark of your tree during the winter which can injure or even kill the tree in severe cases. As fruit trees age, their trunks become thick and much less tasty to critters and they tend to only go for older trees in cases of extreme food shortages. 

Spiral guards should be placed on the trees in the fall (late September through early November) and then removed in spring (late April/early May) to avoid potential problems for your tree. Several factors will contribute to trunk damage if spiral guards are left on a tree all year round:

• Moisture buildup can cause rot and can cause a young tree to begin developing roots above-ground at points of contact that have high enough moisture (roots can be seen in example photo below).
• Debris collecting behind the spiral guard attracts insects which could damage the trunk.
• Girdling damage can happen, especially if the spiral guard gets stuck in place due to tufts of grass or another factor.
• Overheating can be an issue, especially with black or dark brown spiral guards that absorb the sun and create an unnaturally warm environment at the base of the tree.

These issues are most likely to occur if your guards are on an older tree (3+ years old) where the guard is tight around the tree, and the issues will get worse the longer the guards are left without maintenance. We know this because we accidentally (and mistakenly) left white spiral guards on some of our young test orchard trees for 2 seasons in a row; this photo shows what we saw this fall when we completed regular maintenance and kicked ourselves for not prioritizing doing our maintenance properly. Fortunately, only a couple of our trees sustained enough damage that we might have to replace them (though they also may pull through), and the rest should grow through it without trouble. The roots in this photo will die back and prune themselves off with exposure to air next spring (we still placed spiral guard protection  back on for the winter).

A young 1- or 2-year-old tree with a loose spiral guard is not at nearly as much risk of these issues, but why set yourself up for a bad habit?

Removing spiral guards in spring after there is lots of other new green growth for the critters to feed on will ensure your trees can breathe and grow freely, without risk of trunk damage that can impact them for years to come. If rabbits are still eyeing your tree as a tasty treat outside of winter, see the hand-made mesh/5-gallon pail protection method below.

Bait Stations

Tamper-resistant/pet-resistant bait stations are a method of rodent control that works well for in our test orchards and out in our fields of young trees. We place them along the rows and check them regularly to confirm the bait is still there over the winter (and remove carcasses), which gives us an idea of where high rodent activity is for continued monitoring or additional control measures. During the winter we don’t see other animals besides rabbits out in the orchard and field, so we are able to safely use this critter control option. Keep in mind that if your trees are right in your backyard and you have pets or children, this method may not be an option for you.

Deer Fencing

Deer fencing is the most effective method of protecting your trees from deer.

Fencing the Orchard Border

If you are putting up a fence around an area, it either needs to be either high enough to thwart the deer jumping over it (at least 8ft) or be a double-fence system (two fences side by side) because deer have poor depth perception. If you go for a double-fence system, you will want to install a main fence (8’ tall) on the inside of the system with a shorter (usually electrified to increase negative experience of the deer) fence 3-6 feet away from it on the outside, which leaves a gap so that the deer cannot accurately judge if they can clear both fences safely. 

Fencing an Individual Tree

You can also create a barrier around an individual tree. How easy and cost effective this will be will depend a lot on how big the tree is, and at what height the first scaffold layer of branches is. The hand-made mesh barrier protection outlined below can be used for individual trees, adjusting the height and diameter of the barrier to match the tree size and height you need.

Other Deer Deterrents

There are also methods of deterring deer with various repellents. There are lots of options on the market as well as DIY things you can find by researching online. I’m not going to get into any of them here since I don’t have much experience with any that have worked consistently enough to recommend. This is not to say they wouldn’t work, but they definitely require regular re-application, which then adds another task to stay on top of (and is likely the reason deer repellents haven't worked successfully for a full season for us). In addition, with the current scale of our area, we also would need a significant number of repellant stations and installing a deer fence was worth the expense. However, deer repellents may work quite well for small orchards or backyard growers!

DIY Critter Protection Options

Here are some easy DIY ways to provide an extra dimension of protection so rabbits can’t reach over the spiral guards to nibble your trees.

Metal Mesh Cage-style Barrier

Create a simple cage-style construction of wooden stakes (2-4 stakes depending on barrier diameter) supporting wire mesh from a hardware store. This can be modified in height and diameter and made with lighter or heavier-duty metal mesh and stakes, depending on what you need. If you’re just blocking rabbits, you can go shorter and lighter duty as per this photo of my dad’s hand-made barrier protectors. However, if you’re hoping to barricade deer, you’ll likely need to go taller, wider diameter and heavier duty, with stakes being pounded in deeper.

5-gallon Pail Barrier

If you have access to used 5-gallon pails, this might be a great DIY option for you. This method is one of my dad’s favorite cheap ways to both visually mark and protect his baby nut tree seedlings as well as other seedlings that grow slowly and get planted out when they still aren’t tall enough to reach over the top of the pail.

To use 5-gallon pails, you’ll need to saw off the bottom of the pail and then just slide it over a young tree to make a great barrier for multiple years! You’ll still need to ensure you visit to pull weeds away at the base of the tree, and we do still use spiral guards because sometimes mice and voles will tunnel under. You’ll also still need to monitor snow levels as outlined below, and this barrier will not stop deer at all.

5-gallon pails can be left in place for several years – my dad often leaves his in place for so long that he has to saw them off because the tree has gotten so big that while it isn’t close to girdling the tree, the bucket cannot fit to slide it back off over the top – the tree trunk has reached 4+ inches in diameter and is both too tall and branches not bendy enough. Over time the plastic of the pail may get brittle from sun and freezing, so be aware that you could find some sharp edges or need to tidy up plastic bits when you’re doing your weeding and mulching maintenance. The pail might even end it’s function due to brittleness before you need to saw it away.

The final bonus of the DIY 5-gallon pail protector is that it helps protect the trunk when you’re mowing (especially weed-whacking), so you get a double function, multi-year critter barrier. If you have other materials that you can re-use in a similar manner, don’t hesitate to get creative!

What Methods are We Using for Critter Protection?

We have deer fencing around the test orchard and crop fields at True Root Tree Co. (dad’s property), where we also utilize spiral guards and pail/mesh tree guards. In the Silver Creek Nursery crop areas and other test orchards, we use spiral guards and bait stations. Our staff also do weekly field and orchard walks to check bait stations and catch/prevent damage before those hungry critters can totally decimate a tree, adding more spiral guards or creating decoy piles of tasty, freshly-pruned branches (during dormant pruning time) if needed. While it wasn’t mentioned above, if you can tell where rabbits are living by following tracks in the snow, you can absolutely use some of your dormant prunings to pile between your tree(s) and the critter’s possible home to distract them from venturing out quite as far.

The Importance of Field and Orchard Walks

Does it snow heavily in your area? I just want to take a moment to reiterate the value of regularly walking through your orchard areas during the winter (and summer, for that matter!) Especially after snowfalls that don’t melt away, it’s important to check that your spiral guards are reaching up as high as they need to block nibbling mouths!

Last winter we had lots of snow that didn’t melt away quickly and over time, built up to layers several feet deep. This was especially hard on some of our new growers who hadn’t realized the rabbits would bound lightly across the top of the snow and easily be able to reach above their spiral guards. All the folks who had this happen have already learned that lesson the hard way, having to prune away girdled branches and hope their tree can bounce back from the damage. If you’re reading this, you can plan ahead and try to avoid that growing roadblock!

Despite mulching and fall orchard care seeming like an easy topic, I’ve now spent over 3500 words talking about it! There are always new things to learn about the soil and growing, and sometimes it’s nice to do a comprehensive review as a reminder. I hope this blog post helps you along your journey in growing healthy fruit trees!

I need to pop out and take some additional photos of my dad's pail protectors and metal mesh barriers in use! come back later this week if you need a visual of them!