Chapter 16: Trees

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Welcome to the Deep Dive.

This is where we take source material, really dig into it, and pull out those key insights you need to get truly well informed on a topic.

Today we're looking at something maybe we see every day but don't always think deeply about, trees.

Our main guide here is Barbara Damrosch's The Garden Primer.

And you know, whether you're maybe planning a garden for your future place, thinking about green spaces on campus, or you're just really curious, this is designed to get you up to speed quickly on, well, pre -care.

It seems simple, but it's surprisingly complex.

There's this real connection people often have with trees, isn't it?

They're not just plants, they sort of become companions, like old friends watching things unfold.

You might think of say a big sugar maple that cooled your house down, totally solid, dependable.

Or maybe one of those weeping willows, kind of irresponsible, dropping branches everywhere, but still, you know, totally charming.

They each get their own personality.

That connection really speaks to their nature, doesn't it?

Their longevity.

Trees often outlive us by a long shot.

They add this incredible value, this grandeur to a place.

But that's also the challenge.

Planting a tree isn't like planting annuals.

Mistakes you make early on, although they might not show up for years, maybe decades, and fixing them later, it gets really hard, really expensive, sometimes impossible without just starting over.

So this deep dive is kind of a shortcut to avoiding those future headaches.

Okay, let's unpack this then.

Starting with the really big decision.

How do we choose the right tree for the right place?

Seems foundational.

Yeah, it's about more than just, oh, that looks pretty.

You've got to balance how it looks with what it actually does.

I mean, the beauty can come from lots of things, right?

The overall shape, leaf color, maybe texture, flowers, fruit, even the bark can be stunning.

Like think of a copper beach, those dark red leaves that massive form, the smooth gray trunk.

It's incredible.

Or a paper birch, that bright white bark, the way the light filters through the leaves.

Exactly.

And it's not just one season.

The best trees offer something all year round.

You get spring flowers, maybe amazing fall color.

Then in winter, you might have interesting bark, like a river birch peeling or the red stems of an Amur chokecherry.

And evergreens, they give structure when everything else is bare.

Plus, some fruits hang on through winter, which is great for wildlife too.

Okay, so beauty is one aspect, but what about the jobs trees can do?

You mentioned purpose beyond just looking good.

Oh, definitely.

There were courses.

Take shade, for example.

A deciduous tree, planted smartly, especially southwest of a house, its leaves in summer can seriously cut down on cooling costs.

Then winter comes, leaves drop, and suddenly you're getting that welcome sunlight warming the house.

Dense trees like meeples or beaches give deep shade.

Others like birch or redbud offer more, you know, dappled light.

That makes sense.

And wind breaks.

How do trees work for that?

They're actually better than solid walls sometimes.

Instead of just blocking wind, they sort of absorb its force, slow it down, creates a much calmer spot.

Evergreens like spruce, fir, pine, those are the classic choices for year -round wind protection.

But even deciduous trees planted close together, like beech or linden, can make a big difference when they're leafed out.

Right, and for privacy, like visual screening.

Yeah, for that you want trees that keep the branches low to the ground.

Columnar types are great, like a century ginkgo.

They make a nice green wall instead of a fence.

And then there's bigger scale stuff, like erosion control or reforestation.

Pines are fantastic for holding soil on slopes.

Your local soil conservation district can be a huge help with projects like that.

Even providing seedlings sometimes.

It sounds like the main takeaway here is shifting focus.

It's not just what we want, but what the tree needs to thrive where we put it.

It's about matching the tree to its home.

That's precisely it, and the absolute number one factor in that match.

Space and scale.

You have to picture that tree fully grown.

It's such a common mistake, planting a cute little blue spruce near the house, and then 30 years later it's 80 feet tall and completely dwarfs the place.

It's heartbreaking actually.

For big shade trees, even if they're deciduous, plan for at least 20 feet away from the house.

Stops branches hanging over the roof, roots causing problems.

If space is tight, look at smaller ornamentals, magnolias, maybe hawthorns.

Lots of great options.

Okay, visualizing the mature size is key.

How else can we avoid those mistakes that only show up, like way down the road?

Well, tied into visualization is doing your homework.

Go visit botanical gardens, walk around older neighborhoods in your climate zone, see what these trees really look like when they're mature, and try not to get taken too much with novelty, as Damarosh puts it.

That really unusual tree might look cool now, but a whole yard of oddities can look messy later.

Start with reliable basics, then add accents.

Remember, this tree is probably going to be there longer than you are.

That's a good point.

What about climate?

Hardiness zones are helpful, but are they the whole picture?

They're a starting point, definitely, but they don't account for everything.

Microclimates, elevation differences, weird local conditions.

So especially if you're investing a fair bit in a tree, talk to local experts.

Your nursery, an arboretum, the local extension service, they know it really thrives in your specific spot.

And they can advise on protecting slightly tender trees for the first few winters.

Soil moisture is another huge one.

Most trees actually die from having their roots constantly wet, not dry.

So check your drainage.

If it's damp, pick something that likes wet feet, like a red maple or a willow.

If it's dry, go for drought -tolerant species like red cedar or maybe palo verde, depending on your region.

And then there are specific site conditions, like shade or being near the coast.

Exactly.

If you have a really shady lot, you need forest natives like hemlocks or maybe certain maples, coastal areas.

You need trees that handle salt spray and one Japanese black pine, white spruce, things like that.

And cities.

Cities are tough on trees, aren't they?

Oh, incredibly tough.

You've got soot, pollution, soil that's compacted and often dry, heat bouncing off pavement, road salt in winter, even dog urine.

It's a lot.

But some trees are remarkably tough.

Magnolias can do well.

Ginkgos are legendary city survivors.

Red oaks, too.

There are definitely resilient options.

OK, and what about pests and diseases?

How much should that factor into the choice?

It definitely should.

Again, your local extension service is your friend here.

They know what common problems hit which trees in your area.

But the absolute best defense against pests and disease, it's a healthy tree.

Simple as that.

If you choose the right tree for the right place, give it good soil, enough water, proper light.

It can fight off most problems itself.

Prevention starts with good siting and care.

That makes sense.

Which brings up this trade off, fast growth versus a long life.

People often want quick results.

They do.

It's totally understandable to want shade fast.

But those super fast growers, willows, silver maples, poplars, they often have downsides.

They tend to have weaker wood, more prone to breaking in storms, shorter lifespans generally.

And their roots can be really aggressive.

Seeking out water lines or septic systems, it can cause major problems.

So making a choice that lasts.

What does that really boil down to?

It boils down to investing that time up front, research, planning, really thinking it through.

You're choosing something not just for today, but potentially for decades, maybe even centuries.

You're essentially building a living legacy.

Okay, so you've done the research, made the choice.

Now the practical part, getting started.

How do we give that young tree the absolute best start?

Well, when you're buying, often smaller, younger trees are actually the better bet.

They tend to establish more easily, they're cheaper.

And you can usually plant them yourself.

You can even get bare root trees, often mail order, which gives you a huge selection.

They look like sticks, but they take off surprisingly well if planted right.

I see the logic and patience there.

But sometimes you really do want a bigger impact sooner, right?

Like if you move to a new place with zero trees.

Oh, absolutely.

If you need that immediate shade or a windbreak right away, investing in a few larger, professionally installed trees can be totally worth it.

It makes a huge difference fast.

It's just a balance of cost, effort, and immediate need.

Now once you have the tree, protecting it when it's young is absolutely critical.

We need to talk about girdling.

That's when the bark is damaged all the way around the trunk.

It cuts off the cambium layer just underneath, which is where all the nutrients and water move.

It's fatal.

There's a tricky process called bridge grafting that can sometimes save a tree, but honestly prevention is key.

Okay, so what are the biggest dangers to young trunks?

And how do we prevent that girdling?

Animals are a big one, right?

Rabbits, mice, voles, deer.

They seem to love chewing on young bark, especially over winter.

They really do.

The best defense is usually a cylinder of hardware cloth that's sturdy wire mesh.

Make sure it's buried a few inches in the soil so critters can't tunnel under and tall enough to be above the snow line.

But there's a catch, isn't there?

A huge catch.

You absolutely must remove that collar or expand it as the tree trunk grows wider.

If you forget, the protector itself will end up griddling the tree it was meant to save.

Happens all the time.

Oof.

Okay, what else damages young trunks?

Winter sun can be harsh.

It warms the bark on sunny days, then it freezes hard at night, causing cracks called sunscald.

Wrapping the trunk with burlap or a special tree wrap helps.

Some people even paint trunks white with latex paint to reflect sun.

But those commercial wraps, take them off in spring so the bark can breathe.

And the classic lawnmower disease.

Ah yes.

Damage from mowers and string trimmers bumping the base.

The single best solution, mulch.

A wide circle of mulch around the tree keeps equipment far away.

Simple, effective.

Near driveways, maybe a few low stones as a barrier.

Okay, what about staking?

Do all young trees need stakes?

I see them everywhere.

Actually, our understanding of staking has really changed.

There's this fascinating process called a thigmomorphogenesis.

Basically, trees respond to wind stress, the swaying motion, by growing stronger, sturdier trunks.

It's like exercise for the tree.

So if you plant a tree correctly, with a good root ball, it often doesn't need staking at all.

The wind helps it get strong.

If it's a really windy spot, or the tree is very tall and skinny, maybe use short stakes, tie loosely just for the first year, then get them off.

Too much staking makes for a weaker tree long term.

That's really counterintuitive, but makes sense.

So the tree's in, it's protected, maybe survived its first year without stakes.

What about ongoing care once it's starting to get established?

Well mature trees often fend for themselves, but young trees still need support.

Watering is number one.

But not just a quick sprinkle every day.

They need deep, infrequent soaking.

Really get the water down to encourage deep roots.

You can make a little berm, like a dirt saucer, around the tree to hold water.

Or use a soaker hose spiraled around.

Even a 5 gallon bucket with a few small holes drilled in the bottom, fill it up and let it slowly seep in.

Deep roots mean more drought resistance later.

And mulch goes with watering, doesn't it?

What's the best practice there?

You want a good layer, maybe 3 or 4 inches thick, of organic stuff, shredded bark, woodchips, even chopped leaves.

It holds moisture in the soil like crazy, stops weeds, and protects roots in winter.

It's hugely beneficial.

Absolutely.

But one key detail.

Pull the mulch back about 6 inches from the actual trunk.

Don't pile it right up against the bark.

Why's that?

Rodents.

Voles love to tunnel in deep mulch right next to a trunk and chew the bark over winter, especially under snow.

Leaving that little gap, or maybe using gravel right near the trunk, discourages them.

Basically, mulching kind of mimics the forest floor where trees evolved.

It makes them feel at home.

Okay, watering, mulching.

What about feeding?

Do trees need regular fertilizer, like say, roses or vegetables?

Generally, no.

Not established trees in decent soil.

They usually find what they need.

Young trees, though, can benefit from a feed once a year, usually in late fall after they've gone dormant.

Compost is great.

Just spread it out under the tree, aiming for the drip line.

That's the area on the ground directly under the tips of the outermost branches.

That's where most of the active feeder roots are.

For really big, mature trees, remember, their roots go way beyond the drip line, sometimes two or three times the canopy width.

Deep root feeding with special tools, that's usually only for trees that are really struggling.

Got it.

Now, pests and diseases.

This feels like the scary part for big trees.

You can't exactly spray a giant oak easily or safely.

You're right.

It's a different ballgame than with smaller plants.

That's why prevention is absolutely paramount.

It goes back to choosing the right, resistant tree for your site and keeping it healthy.

Good soil, proper water, mulch.

Enough sun, a healthy tree can fend off a surprising amount of trouble on its own.

Its natural defenses are strong.

But if problems do pop up, what can a homeowner realistically do?

Well, you can prune out infected bits, like branches with fire blight or cankers, that stops the spread.

Raking up and getting rid of diseased leaves in the fall is crucial for things like apple scab or leaf spot diseases.

Dormant oil sprays, applied before leaves emerge, can smother overwintering scale insects or mite eggs.

Borers, insects that tunneled into the wood, those are tougher.

Sometimes barriers help.

Sometimes you might need targeted treatments.

But honestly, if you suspect a serious disease, get it diagnosed properly.

Your local extension service often offers that.

And don't give up too quickly.

Trees can be incredibly resilient.

They might look awful one year and bounce back the next.

Okay, so sometimes this tree just looks off, not thriving.

But maybe it's not an obvious bug or disease.

How do you play detective and figure out what's stressing it out?

That's a great way to put it, playing detective.

You have to look at the whole picture, the environment.

Are the leaves scorched and wilted?

Maybe the soil's just too dry?

Or are leaves turning brown?

Maybe branches dying back from the top?

That could actually mean the opposite.

The soil's too wet, poor drainage, roots are suffocating.

Is the tree just generally declining, looking thin?

Could be compacted soil from foot traffic or construction nearby?

Aerating and adding organic matter and mulch can help there.

Did construction happen nearby?

Even digging a trench several feet away can damage crucial roots.

Feeding and mulching helps recovery.

Did the soil level around the trunk change?

Removing soil exposes roots.

Adding soil smothers the trunk, both are bad.

Adding soil needs a properly built tree well.

What about nutrient issues or climate problems?

Yeah, pale or small leaves, maybe fewer flowers than usual.

Could be a nutrient deficiency.

Fertilizing might be the answer.

Did buds get zapped by a late frost?

That's a climate or sighting issue.

Maybe needs a more sheltered spot or a windbreak.

And toxic stuff, pollution, salt?

Air pollution can scorch leaves.

Ground pollution often looks like drought stress.

Herbicide drift causes weird, distorted growth.

Road salt typically kills branches on the side facing the road.

Solutions vary, washing salt off, choosing salt -tolerant species like certain oaks or hawthorns.

It really is detective work.

OK, last big topic, pruning.

Shaping the tree for health and looks.

Sounds like the principles are similar to pruning shrubs.

They are, fundamentally.

You prune to encourage branching where you want it.

Maybe increase flowers or fruit, thin out the canopy to let light and air through, or reduce wind resistance so it's less likely to break in a storm.

Specifically for trees, you're looking to remove branches that are growing inward toward the center or straight up or straight down or crossing and rubbing against others.

You also want to deal with weak V -shaped crotches, competing main stems or leaders, and those vigorous vertical shoots called water sprouts or suckers coming from the base.

And you said earlier, doing the major shaping when the tree is young is really important.

Yes, much easier, much safer.

And it sets the tree up with a good structure for life.

You can do a lot of careful shaping on a small tree with hand tools, standing safely on the ground.

But once that tree gets big,

seriously,

leave the chainsaw work and climbing to the professionals,

certified arborists or tree surgeons.

It's just not worth the risk.

You're definitely not Paul Bunyan up a ladder.

Couldn't agree more.

For mature trees, the only pruning a homeowner should really tackle is removing dead or broken branches they can reach safely from the ground.

And when removing any large ponch, learn the proper technique.

Make an undercut first, then a top cut further out, then the final cut just outside the branch collar.

That swollen area at the base of the branch is critical for healing.

Never cut flush with the trunk.

And what about treating the wound?

People used to talk about tree paint or filling cavities.

Yeah, that thinking has completely changed.

Research shows trees heal best on their own by compartmentalizing the wound, basically walling it off internally.

So just make a clean cut, maybe smooth the edges a bit, but never apply paint or filler.

It can actually trap moisture and encourage decay.

It all comes back to knowing your limits.

Some things like maybe installing cables to support weak branches are definitely jobs for the experts.

They have the skills and equipment.

It's about being a responsible caretaker.

Well, this has been quite the journey.

We've gone from that deep emotional connection we feel with trees all the way through choosing them carefully, getting them started right, and providing that long -term care.

And the main thing I think is that success isn't just luck or guesswork.

It's about understanding how trees work, what they need, and committing to them for the long haul.

Applying these ideas isn't just about having a nice yard.

It connects to sustainable living, organic practices, improving the environment, and really just becoming a more successful and knowledgeable gardener overall.

Thank you so much for joining us on this Deep Dive.

And before you go, here's something to think about.

Look around your neighborhood.

Is there a mature tree you really admire?

Based on what we talked about today, why do you think it's thriving so well right there?

Or flipping it around, if you could plant any tree,

what's the first thing you'd wanna find out about what it needs to succeed?