Garden School:


Garden School:
Teaching this week: Basic tool fitting - right tool, right size.

Saturday, 31 March 2018

Permaculture, Forest Gardening, Square Foot Gardens

Recently, a friend of mine ("Hi, Katie!" *waves*) sent me a link to this quite incredible story on a blog in America: the headline reads "Permaculture Garden Produces 7000 Pounds of Organic Food Per Year on a Tenth of an Acre" 

Is that weight or money? Oh, it's America, must be weight. That's just over 3 metric tonnes, or 3½ American tons, of food.

Here's what it looks like:

 Well, that is pretty awesome, I have to say.

The story (which you should read for yourselves - go on, follow that link and check it out, it's quite short) tells of a chap living in downtown Los Angeles, who got fed up with the money, time and water he spent on his lawn, and decided to rip it out and grow veg instead.

They now proudly claim that it's producing 90% of their vegetarian diet, plus they sell $20,000 of plants each year, so it gives them an income as well. And they don't use any artificial fertilisers at all.

OK, so far, so lovely.

And it is lovely: it's a great story, and it is something that should inspire us all to have a go. The daughters of the guy who started it say "he took over every square inch, horizontal, vertical, the frontyard, the backyard and the driveway".

But there are a couple of caveats that I would like to mention.

Firstly, Los Angeles.  The climate there is somewhat different from ours in the UK. Note the lack of any sort of greenhouses - they just don't need them. Their idea of winter is 20 degrees C (dropping down as much as 10 degrees overnight, ooh!), so as far as we are concerned, it's summer all year round.

Secondly, looking after this garden is going to be a full time job. Don't imagine that you could just potter around for half an hour each evening. This is intensive farming.

"Everything is done by hand," they say - there isn't room to hoe, because the plants are so densely packed, which in principle, means that there is no room for weeds, but we all know how well that works out, don't we..... and we have to assume that they are picking the bugs off by hand, constantly, as well. No chemicals, remember?

They make a big deal out of how they don't deplete the earth in the way that modern farming does: they aim (as any sensible gardener does) to increase the fertility of the soil by constantly adding organic matter, and by the use of deep no-dig beds, and one of their philosophies is to ensure the soil is covered with foliage at all times:  no bare soil there! They get, on average, no rain at all there between May and September, by the way, hence their emphasis on avoiding water loss through evaporation. But no matter what they call it (and they, apparently, hate the word Permaculture, denying that it's built on Permaculture principles at all), it is intensive farming.

Thirdly, this is a dry, dry climate: in the UK, if you crammed plants together like that, you'd have mould, mildew, slugs, and snails to contend with.

Fourthly: preparation, preparation, preparation. The article tells us that they spent from 1999 to 2007 improving the soil: now that's what I call preparation. They say that it was pretty much the poorest soil you can get, when they started, but still, eight years!! But that's what you need to do if you want to farm as intensively as this: the soil has to be absolutely top notch before you even start.

Fifthly (still not sure if that is a real word), presumably they have to watch the place like hawks night and day to prevent incursions from animals, thieves and vandals. The concept of turning your front garden and drive over to growing plants is an excellent one, but you do have to consider the neighbourhood, the wildlife, and the risk of damage, theft, and/or contamination.

I hardly need mention the danger of such intensive cultivation with regard to pests and diseases: one vine weevil in there, one butterfly laying eggs, one tiny speck of disease, and the entire garden could be infected within days. With no gaps between anything, it would be impossible to stop it spreading all over a bed, and then from bed to bed.

They also produce 2,000 eggs a year - that's probably ten birds: I can't see from the photos where the hens are kept, but I imagine they have to be firmly penned in to keep them out of the food beds.

So that's me, pointing out some of the negative aspects of this article, as far as we in the UK are concerned.

But what good points could we take from it?

Well, for a start: who needs a great big lawn in front of their house? I'm not a big fan of lawns, I don't have any in my own (very small) garden, and I am all in favour of turning them over to something more useful: as long as it is fenced and protected, and as long as you don't fall out with your neighbours, who might think that your veggies will lower the resale price of their house. As anyone who has grown veg will know, for most of the year, it ain't pretty!

This - right - is two-thirds of my own front garden, turned over entirely to shingle, with plants for sale: everything you can see is in a pot, and everything is available for sale. Or was, last year! There's a different selection now.... but this shows what you can do with even a very small garden.

Then there's the Forest Gardening aspect: don't be restricted by not having much ground in which to grow: think layers, think vertical, use all those garage walls... and garages usually have gutters, so there's an instant source of water for irrigation.

They mention Square Foot gardening, and if you have never heard of this, google it now: it's an interesting idea, well suited to our small UK gardens, and is something that can be gradually increased.

So what am I actually saying? I'm saying, don't look at this guy's garden and imagine that you could get the same results in five minutes: instead, read about what he did and how he did it: do some research of your own: look at your own garden with a view to seeing what areas you would be prepared to turn over to veg: and think about how much time you have available to tend such an area.

Then get out there, and do it!



Thursday, 29 March 2018

Festuca glauca - small blue clumping grasses: to trim, or not to trim?

This is a question which vexes me on a regular basis: several of "my" gardens have these small rounded decorative grasses, and every year in autumn, I have to decide how to manage them over the winter.

My standard method is to rake out all the dead grass, using my faithful daisy grubber and/or my gloved hands.

Gloved? Always gloved, when dealing with grasses, as  you never know when they are going to give you a sly paper cut.

It's like combing out the tangles in your hair: you keep on combing until the daisy grubber runs through with no resistance, no matter what angle you use. Then you know you have truly removed all the dead stuff.

But then, there is the question of what to do with what is left. Often the clumps look a bit lanky and scruffy, and the garden owners often ask me to trim them, or "clip" them, so that they look neat over the winter.

I'm never happy doing this, because I think that the beauty of these small grasses  lies in their loose outline: if  you clip them, they turn into topiary and then you have to keep on clipping them, otherwise they look strange when they start to regrow.

It's important to  understand, at this point, the manner in which grasses grow.

Most garden plants grow from the tip onwards: if you cut them - as we do with Box and Yew, to make topiary and hedging, for example - then the cut end will immediately sprout new growth, often they branch out and become thicker. This is how hedges become dense.  This is also the basis of the Chelsea Chop: we cut off the single stem, which then re-grows, usually with multiple new stems.

Grasses, however, grow from the base: new leaves sprout from the centre of the clump.  They grow in rather the same way that our hair does, ie from the root: when we cut it, it continues to grow but the cut end remains cut: the hair is pushed out from the scalp, and the new growth is right there down by the roots,  not up by the tip.

So when we cut the blades of a decorative grass, we lose the tapered point and end up with a blunt tip. This blunt tip does not stop the grass from growing, but it will never regrow into a delicate point, it will always be blunt. This, in my opinion, rather spoils the look of the grass.

In addition, and again, rather like our own hair, each blade of grass will grow for a certain time, then it will stop growing, and in time it will be replaced by a new one growing from the base. So, those cut ends might "move outwards" for a while, or they might sit there, stationary, until they die.

New blades appear in a continual process: faster in spring and early summer, slower in autumn, and not moving very much at all through the winter.

This means that as soon as you clip or trim a clump, no matter where you cut them, new tips will appear in a week or two, because there are always some new shoots on their way up through the clump.

But does this matter? How long does it take to re-grow?

Aha! Time for some citizen science, let's do an experiment.

This garden has, conveniently, two identical Festuca glauca plants, side by side. So they get the same light and water conditions, they are in the same soil, they were planted at the same time (which I happen to know, because I supplied them) and they were the same size when planted.

Perfect!

Here we are in July. They were looking rather brown and battered (sorry, I forgot to take a "before" picture), so I raked them both thoroughly, removing all the dead stuff, which freshens them up, removes several handfuls of what I call "bug hotel", and reveals their nice blue-ness again.

Then I trimmed one of them "to make it neat".

As you can see.

Exactly four weeks later, late August, you can see that the trimmed one has sent out a few wispy bits, which are the new blades of grass "growing out" through the haircut.

It doesn't look too bad.

The  uncut one has filled out, and is again a pleasing dome of foliage.

Here we are again, another two months on: you can see that the chopped one has now more or less regained the proper shape.

But it is still lagging behind in terms of size - it's distinctly smaller.

Both of them are starting to go a bit brown, as we are now well in to autumn.




Here we are again the following spring, not the best of pictures: the one which was cut is still slightly smaller-looking that the uncut one, but it has at least recovered the fluffy shape.

So do we have a conclusion?

Trimming decorative grasses ruins the shape, in the short term, unless you particularly want the sheep-sheared look.

There is no horticultural justification for clipping them, other than "to make them look neat".

It's far better to just rake out the dead matter once or twice a year.

But, at the end of the day, if the owner wants them clipped, then I will clip them!

Saturday, 24 March 2018

What to do with an over-pruned weeping Silver Birch

Here's a picture that could just as well be titled - well, I can't quite think of the right title for it.

 *pause while I hoot hysterically and wipe away a tear of laughter*

The new owners of this tree contacted me today, asking for advice on how to prune it: they correctly spotted that the top *pauses to wipe away more tears and blow nose* is full of dead material which needs to be cleared out, and they commented that is it far from  graceful.

They also point out that because it is right on the corner of two paths, it can't be allowed to weep properly (unlike me, still wiping away tears) as the growth is all at head height.

It has clearly been massacred pruned like this to allow people to walk underneath it, and judging by the thickness of the thatch, and the stoutness of the trunk, it's been done, year on year, for quite some time.

Right, first things first, what is it:  it's a Silver Birch. I can't tell which one: it could be Betula utilis 'Pendula' (although the bark doesn't quite look white enough), it is more likely to be Betula pendula, possibly 'Youngii' or 'Tristis' but both of those would normally be a little higher in the trunk: so I suspect that this is a top-worked tree.

That means that it has been grafted, just like the dear little Salix Kilmarnocks of whom I have written here, here and here. (*laughs*) (I'm laughing because I sound like an air hostess pointing out the emergency exits.) This means that it is never going to grow any higher - those branches are always going to start at that height, and they are always going to grow downwards, so they are always going to be in the way.

Secondly, it is very clearly in the wrong place. No doubt when it was planted, it was a dear little thing, with a skinny trunk and not very many branches, and it was probably thought to be well clear of the paths. However, they didn't take note of what is called "eventual spread", so they didn't take into account how much bigger it was going to get. In fact, I imagine that they were told by the supplier that, being a grafted tree, it would not get any bigger. They should have been told "it won't get any higher, but it will get wider."

Thirdly, it would be possible to get up a ladder and painstakingly remove all the dead branches, which would at least have the benefit of reducing the "Tonga Beach Hut" effect, but it would never regain it's true weeping form, bearing in mind that as soon as it started to re-grow, the new branches would be interfering with passers by again, and would have to be cut back again.

The only solution here, I'm afraid to say, is to chop the bloody thing down. I'm wiping away a non-hysterically-laughing tear at this point, as I hate to see a tree cut down at any time, and I'm particularly fond of Silver Birch, but in all honesty I can't see any way of "managing" this tree that would be comfortable for walkers, nice to look at, and in any way pleasing to the tree.

Cut it down.

Get the tree guys to cut it to ground level and grind out the stump. Fill it with soil, add some grass seed, and by mid summer it should be nothing but a memory.

It would be worth the new owners taking a look at the situation once the tree is gone: why was it planted there in the first place? Was it to stop people cutting over the corner of the grass? In which case, they could plant a small bushy shrub there instead.

Was it to give shade, or to block off an unwanted view looking outwards from the house? If so, plant another tree but position it a lot further inside the grass area - you can see that the trunk is in the centre of a circle of foliage, so measure the circle and then work out how much further away from both paths the trunk needs to be, in order for the foliage to not come into conflict with the paths.

As "chop the bloody thing down" is a bit of drastic solution, I would like you to know that I have given this matter some considerable thought, and I really think it's the best thing to do. However, I did come up with three alternatives:

1) cut the trunk at waist height, and use it as a small table. 
2) cut it at knee height and use it as a seat.
3) cut it straight across the trunk, just below where all those branches sprout out. This would remove the top-worked, "weeping" material and would leave a stout trunk, which is the original Betula tree - probably, from the bark, Betula pendula.

(It's important to point out that Betula pendula, despite the name, is is NOT necessarily a weeping tree: the branches are slender and often drooping, but not weeping like a weeping willow. To get that effect, you have to buy a particular cultivar, or a top-worked one.)

By chopping off all the grafted material, you would be left with, in effect, a pollarded "normal" Silver Birch tree, which would - possibly - re-grow into a multi-stemmed upright tree. This would not interfere with walkers on the path, but it would then become a substantial tree: you can see by the thickness of the trunk that it's a well-rooted, mature tree, and if the rootstock were allowed to re-grow, it might well turn out to be 30-50' tall in time. And it is quite close to the house.

So on balance: sorry, everyone, but my recommendation is to remove the poor thing.

Monday, 19 March 2018

Vine Weevils and what to do about them

A question came in yesterday, concerning the dreaded vine weevils. Before I get to the actual question, here's a bit of background.

What are they, and why are they dreaded?

Well, they are a small, crawling insect which eats the leaves of plants, then lays eggs on the soil around the plant. These eggs hatch into nasty, greedy, little grubs which eat the roots. This causes the plant to die. And this is why we hate them so much.

They have a real taste for plants in pots: you do find them "loose" in the garden, but not that often - however, most people with plants in pots will, at some point, find they have an infestation of vine weevil.

So, Know Thine Enemy.  Here's a picture of the little blighter:

Note the ribbed appearance of the back end, which is usually black but can have splotches of buff/brown/orange: note the jointed carapace, the snouty snout, the long probing bits, the sharply-angled legs.

This is a female - they are all female - and they are born ready fertilised, so they start laying eggs as soon as they are adult.

The eggs are tiny things, they hatch out into:



... these nasty C-shaped grubs. Creamy white colour, note the brown head-cap.

All the books will say C-shaped, by the way, but it useful to know that they sometimes appear to be quite straight. Poking them will usually make them curl into the C shape, though.  These are the ones that do the damage to the roots.

The C-shaped grubs eventually pupate, so sometimes you find these weird things (left): they have lost the brown cap, and have developed rudimentary legs and snouts.

I always think they look a bit like chess pieces at this stage. If you find them, they are still moving, but slowly.


This is the damage which the adults do: "notched leaves".  They sit on the edge of the leaf and chomp out a big piece.

Can be confused with the damage caused by leaf-cutter bees: but the bees do a very neat circular hole, very regular: vine weevils make ragged notches.

Why are they such a problem? Because those grubs will devastate plants in pots: they will eat and eat and eat until the roots are all gone. If you don't spot them, they pupate, hatch, and lay more eggs. Thus the cycle continues, and once you have them, they are very hard to eradicate.

How do you get them?

Usually, they are brought into a garden on an infected plant. Often, regretfully, bought from an otherwise respectable garden centre or nursery... who are the very people best equipped to spot them, and - as plants are their "product" - who should be obliged to ensure that all plants are weevil-free.  However, they are not, and this is why, in a perfect world, we would keep new plants in a quarantine area until we are sure they are not infected with not just weevils, but any other creepy crawley and/or disease.

Of course, in a perfect world, the garden centres and nurseries would do their job properly and ensure the plants are not infected....

Vine weevils can't fly (thank the lord!) but they are very good climbers, and tireless walkers, so in a garden centre or nursery, where the plants are all crammed together in pots, they quickly spread and infect the entire place.  Then, when you innocently bring an infected pot home, they quickly spread to all your other pots, curse them.

How to spot them:

The obvious sign is the notches leaves where the adults have been feeding, but that's not always visible: you could have a pot which  is heaving with grubs, or has just had eggs laid in it, but on which there are no longer any adults, so you won't see any damaged foliage.

Usually, the first people know about it is when the plants start to die. Or if you go to move a plant, and rather lazily pick it up by the plant instead of by the pot (be honest, we've all done it!) and the plant comes off in your hand, leaving the pot and the soil (and the shattered remnants of the roots) behind.

When you tip out the pot, you will either find little air pockets, usually containing a grub, right up against the side of the pot: or, if you shake the plant to loosen the soil, you'll find the white grubs falling out from the centre of the rootball.

What to do:

As soon as you find the first sign - the first notch, the first rootless plant, the first time you tip out a pot and find grubs - you must take action.

Check every pot that you have. Every single one! If you have small pots, or plastic/terracotta ones up to about 3litres, here is the regime:

1) Move them all to one end of the patio, so you can go through them methodically, one at a time.

2) Shake them upside down over a tray, or over a hard path (concrete or tarmac) to see if any adults fall out of the plant. Any that you find, crush mercilessly with your boot, or cut in half with scissors/secateurs.

3) De-pot: turn the pot upside down, knock the plant out of the pot, and check the rootball. If you see white grubs, put it to one side, on the "infected" pile. Feel free to kill any and every white grub that you find: you can squish them by hand - it's ok to wear gloves - you can crush them with the back of the trowel (be warned, they squirt), you can chop them in half with scissors/secateurs/knife, you can drop them into a jar of salty water and leave them to drown (takes days, and when would you be sure?) you can even put them out for the birds, but only if you put them in a dish that they can't climb out of.

4) If you don't see grubs on the outside, pull the plant fairly firmly, to see if it is still properly rooted. If the plant appears to be firmly rooted, put it back in the pot and put in the "probably ok but we'll check again later" pile.

5) If it "gives" at all, then take the pot to a potting bench or tray, and shake off the soil until you can see the roots clearly. Any white grubs, put it in the "infected" pile. If none, wash the remaining soil off the roots by dunking the plant into a bucket of water and swishing it about. This plant is now clear - no adults, no grubs, no eggs - so it can be potted up again, using clean fresh compost. Discard the compost/soil that  you removed: don't put in on the compost heap, as this just spreads them all round your garden: instead,  put in your council wheelie-bin for garden waste if you have one, and if not, collect it all and take it to the tip.

6) Having worked through all your pots, look at how many were found to be infected: if it's only a few, then the "probably ok" ones can be returned to the patio display. If there are a lot of infected ones, then go back to the "probably" pile and go through stage 5 for each one: de-pot, shake off the soil, wash off the soil, repot in clean compost, dispose of the soil.

As for the "infected" ones, go through stage 5 with them but if, when you shake off the soil, there are hardly any roots left, the throw the plant away: unless it is really precious to you, there is no point wasting a year trying to revive it, it is better to go out and buy new ones.

And if you do, don't forget to check them all before you bring them back into your freshly de-contaminated garden: do stages 2, 3 and 4, preferably before you get to the tills.

If you ever find vine weevils or grubs in plants at a nursery or a garden centre, take it straight to customer service and demand to see the manager. Tell all your friends not to shop there, until you are certain that they have dealt with the problem.

"But I have really big pots."

If you have large pots, such that you can't tip them upside down, then spread an old sheet around the base of the plant, and vigorously shake the foliage, ruffling it with your hands, to see if any adults fall out.

Then, see if you can dig around the base of the plant: if the soil is compacted or full of roots, then you won't be able to do a physical check, so your only option is to go for chemical or biological warfare.

Chemical warfare: There are products you can buy to kill the grubs: you dilute it, water it on, and after several weeks it will have killed any grubs. Follow the instructions very carefully, especially in relation to time of year/temperature.

Biological warfare: You buy a pack of live organisms which you water onto the soil: these organisms find their way into the grub, where they replicate and kill the grubs. They can be incredibly effective, BUT they can sometimes be completely ineffective.

Why the difference? If you read the instructions and follow them, only applying the nematodes at the right time of year, within the right temperature range, and before they die, then they will kill all the grubs. It all goes wrong if you keep the pack for too long before using it: or if you apply them at the wrong time of year, or when it's too cold.

Additionally, they don't kill the adults or the eggs, so you will have to apply them again - in spring, and again in autumn, as per the instructions on the pack -  in order to break the cycle.

So, let's get onto Sue's problem: she wrote to me, saying that she found notched leaves for the first time in her garden last year, then found adults, so she applied nematodes in autumn. This spring ("Spring? Have you seen the snow outside??!") she de-potted a rose, planning to plant it out in the garden, only to discover grubs in it.  The question was, is there any way of getting rid of these things for once and for all.

The answer for Sue and anyone else with the same problem is yes - but it will take a bit of work.  Having gone through all your pots and shaken out the adults, shaken out/washed off the grubs and eggs, repotted everything and applied chemicals and/or nematodes as you saw fit, you then have to do the following:

1) Constant vigilance. Once you have an infestation of vine weevil, you have to be continually on the lookout for them. Inspect leaves every week for damage, gently tug on potted plants to ensure they are still firmly rooted, and once or twice a  year, go through all your pots and de-pot the plants to check their rootballs.   This is a good thing to do anyway, as it gives you a chance to see if they are becoming rootbound, or are too dry/too wet etc.  Go out after dusk with a torch, as that is when the adults are likely to be walking around.

2) Be harsh: if you find infected plants, if you cannot be bothered to completely remove ALL of the soil by shaking, and by washing it off, then you must discard infected plants and buy new ones.

3) Always check new plants very carefully, and if possible, quarantine them for a few weeks so you can check up on them before introducing them to your garden.

4) Consider raising your pots onto benches or stands, and applying grease bands to the legs: this is sticky stuff, rather like flypaper but on a roll, which you wrap around the trunks of trees to catch all the non-flying bugs. It works just as well on bench legs, although it's a horrible fiddly, sticky job to get them in place. But, if you are desperate, it's worth doing for a year, to break the cycle of adults-eggs-grubs-pupae-adults.

So there you have it, vine weevils in a nutshell (horrible mental image, why did I say that?): if you get them, it's probably not your fault, but to get rid of them takes constant vigilance and a degree of persistence - but it can be done!