Garden School:


Garden School:
Teaching this week: Lavender pruning, compost problems, and the difference between compost and leaf mold.

Wednesday, 29 August 2018

Edging of beds: how to retrieve an untidy one

Earlier this year I had a fun job: a very large, long border had lost its nice crisp edge, and it was time to restore it.

The edge had been lost for two reasons: firstly and mostly, the planting had grown overlarge and was overhanging the grass in several places, which meant that the grass in those areas had died off.

And secondly, it had been a wee bit neglected for a while, with no-one clipping the edges to keep them straight.

This resulted in a very wobbly edge!

In cases like these, you have to decide whether to restore the original line of the bed,  which would mean removing and/or reducing the plants which were encroaching on the grass line, or whether to re-cut the bed edge slightly further out, in order to accommodate the plants.

Which one to choose? The decision depends on several factors: for instance, is there another bed alongside it or opposite it - if it's one of a pair, they will need to match.

Are there other garden elements nearby, such as gates, hedges etc which need to line up with the edge? Is there enough room for the mower - if the grassy part is a narrow path, you can't remove more of it to accommodate plants if doing so will make it too narrow for the mower.

And, a sensible, practical one - does the edge meander all the way along, or is there just one massive missing bits? There is no need to do a major restructure of the bed edge if there are only one or two badly spoiled patches.

Having taken all these things into consideration, I decided to widen the bed slightly: re-cutting the front edge to allow the plants room to spread.

Step one was to stretch out a line, to see how badly the edge was out of line, and to work out where the new edge was going to be.

This involved measuring the depth of the bed, to ensure the new front line wasn't going off at a weird angle, and showed that it wasn't really all that bad: you can see the typical “in and out” wavy edge. where in some places, the grass has been lost, and in other places, it has invaded the bed.

So I put the line in what seemed to be the best midway position, with the minimum of grass to be removed, but enough to leave a good edge. (The photo above shows my Trainee, learning how to use a half-moon edger.)

In this case, there was another part to the problem:  at the back, there was a narrow grassy strip which was now too narrow for the mower to get along. So, having decided where my new line was going to be, I decided to use the lifted turves to build up the edge at the back. This meant doing a bit of preparation to the back edge, removing a few plants which had taken advantage of the lack of mowing to spread out into the grass. It also meant taking the time to weed the strip of soil which would be turfed, and to get it level and at about the right height.

Right! To work! Firstly, cut all the way along the line, using either a half-moon edger (which is the traditional and best tool for this job) or a border spade with a very flat blade (which is what I normally end up doing!).

Next, lift the damaged turves and lay them aside.

Here - right - is that step, and if you look closely, you can see the slight wiggle where my Trainee did his bit! ("Bless!")

This does not matter in the least: once the job was finished, I went along the new edge with the edgers and just tidied out that minor digression.

You can see that now, we have a nice clear edge to give those plants room to grow and flop forward, without trespassing on the grass.

Thirdly, peg out the line at the back of the bed, cart the lifted turves round to the back, and lay them down with the cut edge outwards.

Any gaps were filled in with loose soil, and over time the grass will grow and fill them.

Finally, remove the line again, and stomp down the “new” turves, then water them well. The back edge is a bit wobbly, as it's quite hard to make a perfect edge with what you might call “variable” hand-lifted turf! That doesn't matter: in a few weeks, the new turf will have knitted into place, and can be trimmed into a good straight line.

There you go, job done: and now, some months later, the new front edge looks great, and the plants are all within it - and as for the back edge, you would never know that it had ever been so badly damaged!

Sunday, 19 August 2018

Cherry tree with damaged bark

I had a question come in the other day, about a small ornamental Cherry with damage to the bark - a whole section of the bark at about chest height was peeling away, and the anxious owner was worried that the tree would die.

Here's a picture of the tree, taken earlier this year: as you can see, quite a big area of damage.


So why did this happen, and what can be done?

Well, the first thing to say is that Cherries are not long-lived trees: an ornamental one can have a lifespan as short as 20 years, which is no time at all in the life of a garden, especially if we buy them when they are four or five feet tall, which means they are already five years old before we get them.

So if you have a Cherry that's been there for more than a decade, it may well be heading towards the end of its life anyway.

The actual damage could have occurred for many reasons: it could be frost damage, where water gets inside a small split in the bark, then freezes. As it expands, it splits the bark.

The original split may have been disease: cherries are susceptible to phytopthera and to bacterial infection, and there's not much we, as garden owners, can do about it - the spores are "in the air" as it were, and there is no way to prevent them wafting in.

Canker is another possible cause: if the crack in the bark is accompanied by a gummy substance or a darkened crust, then the tree may be infected with one of the many fungal diseases known collectively as canker. Like phytopthera, cankers are always hanging around looking for an opportunity, and trees that are stressed due to frost damage, mechanical injury or lack of water are more likely to develop canker.

If you spot any heavily cankered branches, the best thing to do is to prune them out, making sure that diseased branches are burned or destroyed, to prevent the disease from spreading right back into the tree, and into others nearby.

Going back to frost damage, a little internet research suggests that after a chilly winter night, the south- and east-facing sides of a cherry tree may split as the morning sun causes the bark to warm, expand and break.  If this occurs, the tree will heal on its own, but it forms callused scabs, which are less than pretty. To prevent this, the internet suggests that we paint the trunk with whitewash to help reflect light, making sure to do this only when the trunk has no open wounds. I'm not sure I'd actually go that far, myself, would you?

Apparently you can also "wrap the tree with plastic, paper or cardboard to keep it warm while it heals."   Personally I would not wrap any living plant in plastic, as it "sweats" which would worsen the problem. And I'm not keen on wrapping any plant in anything, for that matter, because you are creating a bug hotel which may well be ecologically very sound, but is likely to lead to even more damage to the bark. So much for the internet, then!

Another possibility for damaged bark is herbicide Injury: many weedkillers contain a wetting agent that can cause permanent damage in thin-barked trees, such as cherry trees, especially when the trees are young. So if you have to use weedkiller near your trees, try to stay at least 20-30 feet away from the trunk (not always possible, I know), and only ever do it on calm, still days, so that the wind doesn't waft the spray over onto the trees.

If it makes you feel any better, I have this tree near to where I live:

As you can see, the bark is split so dramatically that it's practically hanging off the trunk, and the damage extends well over 50% of the trunk diameter.

Yet it's been like this for at least five years, and so far the tree keeps soldiering on, undaunted, which is probably a lesson to us all in persistence in the face of adversity.

So is there anything we can do to prevent these problems occurring in the first place?

Yes: healthy, stress-free cherry trees are far less likely to succumb to problems such as splitting bark than trees that are poorly taken care of.

If you are thinking of planting a new Cherry tree, wait until early spring: trees planted then will have plenty of time to develop a strong, healthy root system before winter sets in.

Plant them carefully: prepare a good, big hole, make sure it's the right depth, and make sure you don't damage the trunk when you manhandle it into the hole, especially if it's a largeish one.

Be careful with stakes and ties: never, ever nail or screw the tree tie to the tree (don't laugh, I've seen it done), and check the ties every year to make sure they are not getting too tight.

Water and feed your new tree for the first year, and in subsequent years, if we have prolonged dry periods, give it a bucket of water every couple of days.

Be nice to your tree: if it's planted in grass,  make a clear space all around it for a foot or more - grass is terribly competitive for water and nutrients, and both fruit trees and ornamentals dislike having to compete for these essentials.

There's another good reason for making a small "bed" around their base: many bark problems are caused by damage from strimming or mowing, so if you have a small clear area around the base of each tree, it will reduce the risk of banging the mower into the trunk, or of whipping it bare with a strimmer.

So there you go: damaged bark on ornamental cherries can be prevented - to some extent - by keeping the tree healthy and un-stressed: and if the worst does happen, it's not always fatal. Or at least, not straight away!

Friday, 17 August 2018

Hoeing: why I don't do it

The humble Hoe - or, Lethal Weapon and Death To Plants, as I call them.

Many of my friends work in what I call "Estate" gardens: you know,  those big houses owned by rich posh people who have a full-time gardener, or a team of gardeners: and most of them live and die by the hoe, by which I mean that they use them all the time.

But I rarely use one.

Why?

Well, firstly, what is a hoe? It's a sharpened blade on the end of a long stick, and you work it by pushing it to and fro just below the surface.

The principle is to chop tiny weed seedlings off before they get started: the dead top part dies in the hot, dry sun, and the root below the surface dies with no leaves to support it.

This only really works on hot dry days, on tiny weed seedlings, with no valuable plants nearby and big gaps between the proper plants: perfect for allotments, in fact, where the crops grow in neat rows, or for the afore-mentioned Estate gardens where they tend to have very large clumps of specific plants, with large gaps between them, making it easy to hoe.

In most of my rather smaller gardens, the beds are packed with a mad variety of plants, in various stages of growth,  and there are no straight lines or obvious gaps at all, such that hoeing is far more likely to chop down something precious than to just get the weeds. Furthermore, most of my gardens don't have those convenient tiny annual weed seedlings: oh no, they have horrible things like bindweed and couch grass, to pick just two at random from the list - and these weeds do not respond favourably to having their heads chopped off. In fact, they see it as "pruning" and they respond by growing even more -  oh woe! So no, I don't hoe. Ho ho. *bits tongue and resists urge to make jolly santa joke*

Hoes come in several different styles: mostly it's a flat-ended blade, but there are also Swoes:

 these are shaped rather like golf clubs and are much better for gardens - as opposed to allotments - as the head is much smaller, and you can, to some extent, work around plants, although they really only work if  you have good big clear gaps between each plant.

This one belongs to a Client, and I do use it for the Rose bed, which has no underplanting at all, so it's much quicker to hoe than to hand-weed: not to mention being able to get in amongst the roses without being scratched to death!

They can also be used, during the June Drop season, for playing Swoe-Apples, a game I invented where you use the swoe rather in the manner of a golf club (with overtones of lacrosse, as you have to hold it in front of yourself) to flick fallen apples off the lawn into the beds, where they can rot down and add organic matter to the soil.. Two points for a clean flick: lose one point for an apple that poings backwards. Beats all that bending down to pick them up!

The second reason I don't hoe (apart from in the rose bed, as mentioned) is that you then have to go round and gather up all the dead chopped tops, otherwise they die on the surface and look horrible. Clients would complain.  Again, in an Estate garden you are working on a large-scale: big clumps of plants, to be seen from a distance, often a considerable distance: so it doesn't matter if there are some dead bits adding to the brownness of the soil, in fact they are probably some kind of lightweight mulch, as far as those beds are concerned.

But in my small gardens, the Client can see every inch of every border: it's a far more intimate experience.

Thirdly, there is the dreaded "pan": this is the technical term for a crust of soil which builds up on or near the surface, which prevents water (rain, irrigation) from soaking in and doing some good. Instead, it sits on the top in flat puddles, then when it dries out, it makes the pan even worse. Frequent hoeing without any sort of digging can lead to this problem.

Fourthly, no matter how good you are with a hoe, there are many occasions where you just can't get the hoe right up to the base of the plane: either there are obstacles, such as low-growing branches (I'm thinking of some particular Roses...) or you dare not risk accidentally chopping the stem. So you end up having to get down on  your knees and hand weed anyway!

At this point, one or two people might be shouting "flame gun!" at the screen: these are long wands with a small blowtorch at the end, powered by either a replaceable gas canister, or a refillable paraffin tank. They are promoted as being an organic alternative to chemicals, for paths and drives. Organic! A complicated,  metal-and-plastic device, using either single-use non-recyclable pressurised cans of gas, or using paraffin (also known as Kerosene) which is a highly toxic fossil fuel derivative which is also used as rocket fuel (look it up yourself, it's evil stuff). Not what I call "organic".

Also, flame guns are notoriously ineffective: they scorch off the top growth, but they don't kill the roots at all, and most weeds/unwanted plants just grow back. Furthermore, their eco-footprint is terrible! And (more to the point) they cost a lot of  money in fuel, as those gas cylinders don't last very long. Not to mention the danger of setting fire to the garden, or to yourself.

So what do I do, if I don't hoe? I use the much-loved Daisy Grubber:


... one simple hand-tool, no moving parts, nothing to break down: they cost just a couple of pounds, and each one lasts for many months.  I dig the weeds out by the roots, while loosening the soil as I go, which I call "fluffing up" the beds, and it gives me the opportunity to check everything as I work around it.

And I know that a weed which I have physically removed is NOT going to grow back!