Garden School:


Garden School:
Teaching this week: Rose pruning (as always!) and water management

Thursday, 25 February 2016

Why put broken crocks in pots?

"...for drainage" comes the instant reply.

Every gardener I have ever known; professional or amateur, beginner or experienced, useless or green fingered, has put broken crocks into plant pots, especially into large, decorative, "permanent" ones.

In recent years, it keeps being suggested that you can reduce the weight of your pots by using a thick layer of polystyrene instead of crocks, before adding the soil - either broken-up bedding plant trays, or those packing peanuts.

But I am going to buck the trend and say "No! Don't do it!"

Why not?

In reverse order:

Polystyrene:

This material is a curse to the environment, to gardeners, to wildlife, and to everyone who has to watch it blowing around and refusing to rot, ever. Putting it in pots may well reduce the weight in the pot, but by doing so it makes the pot top-heavy, so it may be more inclined to tip over in high winds or if knocked.

Furthermore, the roots of the plant will inevitably work their way into and around the polystyrene, no matter what type you use: so when you empty out the pot, pulling out the plant involves breaking up the polystyrene,  leaving little bits of it flying around all over the garden. You can rarely, I find, re-use the same polystyrene blocks more than once or twice, because of this.

They also form a matrix of empty spaces inside the pot, which is a perfect breeding and growing ground for all sorts of nasties which can creep up the drainage holes, not least of which are SLUGS which I have found in disgusting handfuls, when emptying out big pots.

Crocks:

The idea, as with the polystyrene, is to keep the drainage holes clear, to prevent waterlogging of the pot.

But this clearly doesn't work, as anyone who has ever grown plants in pots will know: no matter how carefully you build a teepee of crocks over the drainage hole, when you tip the pot out, you will find a solid mass of earth right down to the bottom, with the crocks embedded in  "jelly mould" fashion, such that every time I am emptying pots for my various Clients, I have to turn the pot-shaped emptied soil ball upside down and dig into it, in order to extract the crocks.

 Here's a perfect example - can you even see the crocks at the bottom?

No - they are completely filled in, smothered, grown around and over by the roots of the plant.

So no, putting in a couple of bits of broken pots does not keep the drainage holes clear.

The other half of the problem is that if you do it properly, by putting in a large double handful of crocks (most people just use three, artistically leaning against each other) and packing it down well, or by putting in a thick layer of sand/gravel, (and this applies to the horrible polystyrene as well) then you are - apparently - creating a discontinuity between the top layer of compost-and-roots, and the bottom layer of crocks-and-air, or sand/gravel. This can sometimes mean the creation of a false, or "perched" water table, which means that the water is held at the junction of the two layers, instead of draining right through.

And this, of course, is exactly NOT what you want!

In this article, the BBC, no less, debunk the myth of using broken crocks for drainage.  They say:

"But a study by consumer magazine Which? suggests it's a myth. Researchers planted 40 pots each with five "Million bells trailing yellow" - a flowering plant prone to root rot in saturated soils. Permutations involved plastic pot, and terracotta pot, and with either saucers or no saucers. Half got crocks, half did not. The plants were recorded for "vigour and flowering impact". The magazine found that the crocks "made no difference to how well our plants did"."

Well, that seems pretty clear.

On the same day, Val Bourne (who I've met at a PGG meeting, very nice lady!) writes in the Telegraph:

" Until this week, for instance, we’ve all been faithfully keeping our old pots and breaking them up before placing them in the bottom of our containers. Now, scientists have proved that's completely wrongheaded. Excess water moves into the coarser material (such as crocks and gravel) once the soil is saturated, thereby creating a watery sump that freezes in the bottom of your pot - killing off your plant’s roots." 

A month earlier, the Telegraph published an article by Ken Thompson, a fellow PGG Guild Member, botanist and all-round jolly good chap, in which he explains the science behind the change in texture of the materials, ie the compost layer on top of the crocks layer: he then summarises thus:

"Exactly the same happens in your plant pot. When you pour enough water in the top of the pot to saturate the compost, gravity overcomes the capillary barrier at the compost/crocks boundary and it drains away through the crocks and out of the drainage hole. But it would do exactly the same if the crocks weren’t there, and when you stop watering, you’re left with a perched water table in either case, crocks or no crocks. The only difference is that if there’s a layer of crocks, the water table is perched at the compost/crocks boundary, and if there isn’t, it’s at the bottom of the pot. So there’s no harm in continuing to bung crocks in the bottom of containers if you feel you ought to, or because your mother did, but be aware that their only practical effect is to reduce the volume of compost available for plant roots."

So there you have it: there is no real point in putting a layer of crocks into pots.

Now, back to the real world: what do I do, personally? *laughs*

I lay a small piece of horticultural fleece down in the base of the pot, then tip in the compost. This keeps ants and earwigs from crawling up into the base of the rootball, and does not interfere with the perfectly normal and natural drainage of the pot. When potting on, it's easy to pull it away from the root ball: and in some cases, it helps to stop the plants pushing tap roots out through the drainage hole and rooting themselves in the shingle!

In addition, at my various Clients' gardens, I usually encourage them to stand their large pots in saucers during the summer, to prevent them drying out too rapidly, but in autumn I go round and turn the saucers upside down, so each pot is standing on a low plinth, to allow extra drainage - and to avoid them sitting with their roots in water - through the winter.

That's all. I have better uses for broken terracotta pots - but more of that later!

New Field Guide: Poppy

Nearly forgot to mention this - I recently released the latest Field Guide, this one is on how to identify the various Poppies that you will find, both in the wild and in the garden.

You can find it here, on the Amazon Kindle Store: and if you are already confident on Poppies, you can go direct to my Author Page, to see which other Field Guides are available, along with the other gardening books which I have published.

As always, a quick reminder that if you have Kindle Unlimited or Amazon Prime, you can download it for free: and don't worry if you don't have a Kindle, you can download it to any ebook reader or tablet, and you can even download it straight to your pc or laptop: Amazon kindly provide a free "app" (or "programme" as we grown-ups call them) allowing this.

So there you go, no excuse now to get confused between Oriental and Opium poppies, or between Welsh Poppy and Long Horned Poppy.  And are you wondering if you can eat the seeds of either of them? (Simple answer “Best not to”, read the book to find out why.)

Of course, I picked the wrong time to release this book, didn't I, as most of the Poppies are annuals, and won't be available for identifying until summer, but sometimes it's nice to do the research in advance...

Friday, 19 February 2016

Tulips in the Frost

It's too darn cold to work today, so instead I thought I'd present you with a couple of close ups of plants in the frost:

Firstly, here are my Tulips: just beginning, no buds yet (and a good thing too, it's 5 below today and they would not enjoy it)



Doesn't this one look rather like a baby bird, demanding food?





Here is a Pulsatilla vulgaris, or Pasque Flower, leaf: every tiny hair is covered with frost.

This is one of favourite plants, Ophiopogon planiscapus 'Nigrescens', which is a lot of name for a little plant: it's commonly known as LilyTurf, or Black Mondo, as the foliage is deep, deep black.

Wasted when planted in a border, but stunning when underpinned with gravel, or something light-coloured.

But today - it's white!



Even the weeds look cute - take this tiny seedling of Hairy Bittercress, it looks as though it's been dipped in sugar!

(Botanically, it could actually be Wavy Bittercress - Cardamine flexiosa - I can't tell the difference at this early stage, but in my garden it is more likely to be Hairy, Caradamine hirsuta.)


Here is a tiny, delicate Daffodil, just about to open, with the frost just melting on the spathe.

And finally, here's another weed, so frosted that it appears to be furry!

Well, there you go, that was a quick trip round my front yard with a hand lens this morning: hopefully just a couple more weeks of cold weather and we will be into spring, oh joy!


Wednesday, 17 February 2016

Cotinus coggygria: time for the annual prune.

February is a good time to think about pruning Cotinus or Smoke Bush: they are mostly strongly-growing, vigorous shrubs that can take over and smother other planting, and they tend to get rather leggy and bare around the base if left to their own devices.

There is another reason for cutting them back very hard each year - you get a much better showing of foliage - bigger leaves, and much closer to eye level!  

Of course, bigger foliage will usually come at the expense of flowers - Cotinus coggygria flower on older wood, so by cutting it back every year you might not get the flowers, but personally I'm not too worried about this, as I tend to grow only the purple-leaved cultivars ('Royal Purple' is my particular favourite) and I would rather have the foliage than the flowers, which are tiny but which appear in a lovely hazy cloud, if we get a good sunny summer.

 Here is a largely unpruned Cotinus coggygria "Royal Purple" in one of my gardens: this was taken a couple of years ago, when we actually had a decent summer, and the fluffy purple haze of flowers makes a lovely contrast to the weeping pear next door, both in colour and in texture.

There's not much sense of scale here, but I can tell you that the flowering starts at about my head height.

If you grow the green-leaved variety, then you might prefer to allow it to flower, as their flowering is much more of a golden affair... but for me, I would only ever give garden space to the purple-leaved ones, on the basis that there is enough greenery in the garden already!

I wrote a piece about annual pruning of Cotinus for GreenPlantSwap last week - so if you'd like to read a little bit about how to do it, head on over there!

Monday, 8 February 2016

Wanted: Slave(s). Formerly called Gardeners.

I'm a member of the PGG (Professional Gardeners' Guild) and it is a running joke within the Guild that some job adverts seem to have been left over from the Dark Ages, when slavery was perfectly acceptable and the lower classes Knew Their Place, and were grateful for a tied cottage over their heads. (Until they grew too old to work, of course, whereupon they were unceremoniously evicted, but that's another story.)

One of my fellow Guild Members was incensed recently over this little gem:

"Gardener 40hr week + Housekeeper 25hr.Would suit couple. - Committed gardener duties include experienced care especially large kitchen garden, general property maintenance, driving, care of pool, cleaning cars, security, handyperson & errands as necessary."

A "large" kitchen garden, huh? Traditionally the work of more than person, just by itself. Then we have the black hole of "general property maintenance"; what exactly do they mean by that - painting the outside? Cleaning third-floor gutters? Washing the windows? Changing light bulbs?

Next we have "Driving". How is your 2-in-1 full-time gardener and full-time maintenance man supposed to get those jobs done while he is out driving, I wonder? Oh, and he has to take care of the pool as well (which probably involves ordering and collecting the chemicals, cleaning out the pump, swabbing the decks, painting the changing room and clearing fallen leaves), AND clean the cars AND deal with security (which usually means being on call all night) AND be a handyperson ... and on top of that lot, he has to run errands as well!

The other half doesn't fare much better. "Housekeeper duties all household cleaning, laundry, cooking to dinner party standard, some help in garden, PA skills helpful."

Now, call me old fashioned, but traditionally a Housekeeper went about checking that the jobs had been done by cleaners, laundry-maids, cordon-bleu cook, etc etc. But they expect this poor soul to help out in the garden as well, but not to exceed her 25 hours/week remit.  (Does she get penalised if she can't get it all done within 25 hours? Is it like the opposite of overtime - you get docked £7 for every hour extra you have to put in? ) And what exactly do they mean by "PA skills helpful", I wonder? Fair enough, they might want someone who can answer the phone with more than "Wot?", but what else do they expect - shorthand and typing?  Spreadsheets and pivot tables? In-depth knowledge of marketing and social media representation for whatever business they are in?

As if all that wasn't fun enough, the advert continues "Both to be drivers and help with dogs and chickens. 4 bed bungalow. Long term position for right couple - start asap."

So they want smallholders, on top of everything else? They are offering a 4 bedroom bungalow, but who on earth is going to have time to fill all those roles if they have children? Or - horror of horrors - are they expected to share it with another couple, which would presumably be the Groom/Butler/IT specialist  (also responsible for wine cellar and investment portfolio)  and his wife the Nanny/ Dressmaker/Nail Artist (with additional experience of ballet tuition to professional level).

And they want these miracle workers asap, which suggests that  the last couple must have walked off the job - or simply died of exhaustion.

Then there was this, from The Lady magazine:

"Experienced Shepherd, Gardener, Handyperson and Driver"

Please note, they want an experienced shepherd. Not an inexperienced one. Notwithstanding the many years it takes to build up the experience you'd need to be a shepherd in the first place, you would have to be a gardener (experienced) as well, and a handyperson (to high standard, no doubt), and yet, in between all those jobs, you would have to smarten yourself up, put on clean clothes and drive these people around. And even that is not as innocuous as it sounds: are they talking about the daily school run, which in itself can easily take upwards of 2 hours a day away from the sheep, the garden, and the maintenance?  Or are you driving one of them into town for a late meeting, getting home at 2am? This has actually happened to one of my colleagues, who was regularly expected to drive late at night, yet also expected to appear bright and early next morning as usual.

Then there was this equally disgraceful one in  Horticulture Weekly, who ought to know better:

"Live In Handyman / Driver / Gardener / Estate Worker Job, Northumberland"

Are you ready for this lot?

"Our client are looking for [their grammer, not mine!] an experienced Handyman to run a large property in Northumberland. This will both be Full Time live in role for a family in a large private house who entertain on a regular basis. This is a large family home which has traditional decor which needs an experienced handyman who has excellent references and attention to detail. You should be able to manage your own time and keep the home to a high standard both inside and out. The Handyman needs to be experienced with general maintenance preferably including joinery and can look after the property and grounds to a high standard. Handyman role is for an experienced and responsible person, with good building knowledge. Work will include the maintenance of the principal residence along with the residential and agricultural property on the wider estate. Candidates should have a sound understanding of Health & Safety in the built environment and have excellent interpersonal skills. Duties to include running errands, helping with airport runs when the family go away, washing the cars, General Handyman role both inside and out the properties and security. A full clean driving license is essential and excellent references will be required. "

There are several aspects of this that make my blood boil: for a start, it reads as though they started out advertising for a couple, then changed it to be just one person. There there is the way that the "handyman" has to be a "joiner" as well, ie can make furniture (or install flat-pack kitchen units?) to a professional standard, and is good enough to maintain their precious house with its "traditional decor" which requires better than the usual mere handyman skills. And the casual use of "inside and out" which could mean insulating the loft, painting the outside, installing new double glazing, fixing the drawers, nailing the roof slates back on, servicing the central heating boiler, oiling hinges, oh, and one of the stairs is squeaking, can you just fix that? I'm not even going to mention the fact that Gardener - my chosen profession - only ranks third out of their wonderful job description.  But what really makes me spit is that they have described three full-time, experienced, professional jobs, and have then tacked on another part-time job - that's the driving part - and yet they still think one person would just love to do it all.

It's as though these people all think that they are living in Downton Abbey, but fail to realise that a real-life Downton Abbey would have a designated person for each and every job.

The whole thing was summed up beautifully by my fellow Guild Member Nicky Howard, who is Head Gardener at a lovely private Estate not far from me:

"You would never see an advert that said "Vacancy for Butcher - must be able to make a Swiss roll, plaster a ceiling and be competent at macramé" Why do they expect gardeners to also be handymen, chauffeurs and small holders??"