Garden School:


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

Sunday, 19 March 2017

Primroses: spring tidy

Here's a quick and easy job to do, now that the Primroses are flowering: go round and remove all the dead and dying leaves from last season.

It's simple to do: just take your secateurs, or a pair of old scissors: locate each clump and snip off the over-large dead leaves.

They are the ones laying flat on the ground, forming a tatty ring around the more upright rosette of fresh new leaves - so it's easy to tell the difference, and easy to get hold of them!

Here's before:


and here is after.

There! Simple, eh? Five minutes with the scissors (ok, in my case, secateurs) and they look so much better.

It's not just for the look of the thing, either: those dead leaves form a combination of shelter and running buffet for slugs and snails, so get out there and snip off the dead leaves!

Friday, 17 March 2017

How to remove Arum Lilies.

Firstly, what exactly are Arum lilies? Proper name, Arum maculatum, improper names include Cuckoo Pint, Lords and Ladies, Jack-in-the-pulpit and, when I was at school, Waggling Willies. It was not a particularly “good” school... but at least we had Nature Rambles!

And secondly, why would you want to remove them? Answer, mostly because they are devilishly generous with their self-seeding, and if you take your eye off them for two minutes, you find that you are over-run with the darned things! The other reason is that the seeds are very unpleasant: they are poisonous, but luckily - well, sort-of luckily - they are filled with saponins, which have needle-sharp crystals, so that if anyone starts to eat them, their lips, tongue and throat immediately hurt and swell up. This is very nasty, but at least it means that "one" is unlikely to choke down enough of the things to actually kill yourself.

Oh, they have their place: if you have large woodland areas to cover, they do a great job, and there is a certain ebullience to their startling orange seeds, later in the year. There is even a garden variety, Arum italicum, with elegantly marbled leaves which can be considered quite desirable.


But for most people, it's the common one that is causing the problems. They are popping up their green leaves at this time of year, shortly to be followed by an elegant wrap-around greenish-white confection, known botanically as a spathe, which is pronounced “spade” with a lisp. No, a lisp at the end, not at the beginning.

The actual flowers are hidden deep inside this spathe, and later in the year, the spathe and leaves will disappear, leaving a stout stalk topped with a cluster of green pea-sized seeds, quickly turning to bright orange. They are incredibly fertile, as anyone who has this plant in the “wrong” part of their garden will know - you start with just one or two, and the next year you are over-run with the darn things.

And there lies the problem - they proliferate too successfully, and they are very hard to remove, due to their structure. Each plant has a long, fleshy stalk which is attached - but not very firmly - to a knobbly, light brown tuber with fat white hair-like roots. This tuber can be as much as a foot underground, in mature clumps, so unless you can dig a hole that deep, it can be impossible to get the tuber out - and of course, if you don't remove the tuber, the plant will grow back next year.

How do I deal with them? Well, if they are not surrounded by other plants, I get out my fork and I dig, dig, dig: the trick is to get your fork in deeply, before you start to lever the plants out, otherwise that fleshy stalk just snaps off the tuber, in rather the same manner as a lizard dropping its tail: ie, no harm is done to the tuber, and it WILL regrow!

If the Arums are in amongst other plants, and large-scale digging is not possible, then it's down on hands and knees I go, with my faithful daisy grubber:

...the technique here is to insert the daisy grubber vertically, just to one side of the target. Push it in as far as it will go, then lever out. With luck, the tuber will be attached, if not, I might have to rootle around for it in the loosened soil.

Here's a clump I dug up specially for you - and there's the daisy grubber to illustrate how deep the tubers are (as you can see, the daisy grubber was only just long enough to do this clump) and to show where to insert the tool, in relation to the clump: vertically, close to one side.
Here's a close-up of one of the plants, showing how the stalk - white, where it's been underground - attaches to the tuber at right angle.

This is the part that snaps off cleanly, lizard-style.

It also shows the lovely tangle of stout white roots which help to keep the tuber anchored firmly in the ground.

From the other angle, you can see that the white stalk ends very abruptly, and that's why it can so easily snap off when you try to weed them out.

 In the very worst cases, where you simply cannot get at the tubers, then don't waste time: use a hand tool to loosen the soil a little, if you can, then just pull up the top growth and don't worry about the tubers. It will take them a year to re-grow, and if you do it again next year, and the following year, then eventually those tubers will run out of energy, as you are depriving them of all their chlorophyll-containing leaves before they get a chance to restock. Eventually, even Arum will get exhausted!

The most important point, though, about getting rid of Arum, is to never, EVER let them set seed. As soon as you see the first hint of orange, pull up the stems immediately, and put them either on the bonfire heap or in the council green-waste bin: don't ever put them on the compost!

 So there's the answer to the Arum lily problem: constant vigilance, never let them set seed, and if you can't dig them out, at least pull their tops off, and don't be surprised if it takes you a couple of years to beat them - but beat them you can!

Friday, 10 March 2017

Repotting House Plants

I'm not an expert on house plants (I much prefer to be outside with my plants!) but the other day I received a question about what compost to use when repotting house plants that were starting to look a bit sad, so here's a quick "Compost 101" introduction to the subject.

When we say "compost" in this context, we mean "potting compost" rather than "made-it-ourselves garden compost".

Why? Home-made compost - and this includes that old standby, "well-rotted manure", now known as "organic matter" - is often unsuitable for potting and for houseplants, for several reasons.

Firstly because it may be "too rich" in nutrients, causing the plants to grow too much foliage at the expense of flowers.  Incidentally, I've put that in quotes, because in one sense, soil can never be too rich, as plants can only take up as much as they can  use. However, with many plants, too much of one particular nutrient - nitrogen - will create tons of leafy growth at the expense of flowers and fruit, so it's usually better to use something which is balanced, ie which contains a desirable balance of the three main nutrients, N (Nitrogen) P (Phosphorous) and K (Potassium). Incidentally, why couldn't they call Phosphorous PH? Then Potassium could be P, and it would be a lot easier to remember. Just sayin'.

Secondly it tends to have a very dense texture, which means it soaks up a lot of water: ideal for the garden, not so good for indoors, as it makes pots very heavy.

Thirdly, this denseness (density?) can cause it to become water-logged, which is very bad for plants in pots.

Fourthly, once the waterlogging dries out, it often becomes rock hard - again, not good for potted plants.

Fifthly (if there is such a word) it may well contain weed seeds, and it certainly will contain an awful lot of creepy-crawlies, including bugs and worms. Now, to have really successful potted plants, you need what is termed "soil life" which means microbes, bacteria, and fungi: these are the engines which break down the nutrients you add in the form of liquid feed and ordinary water, and which make those nutrients available to the plant. Sterile, dead soil will not support healthy plants. However, bugs, and worms in particular, are bad for potted plants: worms create tunnels within the root ball, and air on the roots is very bad. Likewise, there are many bugs that you really don't want on your indoor plants.

For all these reasons, it is better to buy in clean new compost for house plants, and now we are now able to buy "perfect" compost, both for our potting, and for our houseplants, and the name is Multipurpose Compost.

That nice Mr Titchmarsh once said "House-plant compost is multipurpose compost in small bags, especially for people who only need a little at a time".

Yes, it's the same material, sold in small quantities. Does that seem unfair? Not at all: once you open a bag of compost, the nutrients within it start to degrade, so there is no point having a whopping big bag of the stuff cluttering up the shed, if you only need enough to top-dress a couple of house plants.

But if you already buy it for the garden, there is nothing to stop you using it for houseplants as well. I buy cheap multipurpose compost from what are called the Sheds, ie places like B&Q/Homebase, and my absolutely unbreakable rule for cheap compost is to sieve it before using it.

I ALWAYS sieve my compost.  Two reasons: firstly, it gives you a chance to pull out all the contaminants, ie large bits of twig, broken glass, bits of plastic, hard shards, stones, etc. No, I'm not kidding, here's a photo of what came out of just one large bag:

There you go, quite a range, eh? As I said, I always do this - and once, years ago, I sent a similar photo to the manufacturer. Guess what response I got? "We advise on the pack that gloves should be worn when handling this material."  Pff!

Rubbish aside, the second reason is that by sieving it, you end up with three types of material:

1) Large bits of material, usually woody lumps, which are too big to be incorporated in a pot. They are picked out of the sieve (along with the rubbish) and go in the bin.

2) What falls through the sieve is fine, soft, clean, nice to handle, easy to use, and is the basic compost.

3) The third stuff, which is left in the sieve, is what I call the "nuts" of compost: lumps which are too big to go through the sieve, but which are not inorganic or big bits of wood. I use these as a top dressing on pots - perfect for preventing soil compaction, reducing weed growth, and (for those times when you didn't catch the weeds before the got a hold) easy to shake off the top layer, weeds and all, and replace with fresh nuts for an instant top-dressed look.

Here's some pots of Fritillery that I have grown from seed, so they are two years old, and the pots were looking very scabby with moss, weeds etc on them. Not very attractive for sale - but by shaking off the loose stuff, and top-dressing them with compost nuts, they look great, don't they?


John Innes compost is "the best stuff" because it is soil-based (rather than made from coir, bark, or any other agricultural by-product) (which is not meant as a criticism, by the way!) but very expensive, which is why you find so many recommendations for using it in combination with cheaper multipurpose compost. Being soil-based, it contains soil life - those helpful microbes, bacteria and fungi - so using at least some of it will help to get your pots started.

But all compost, John Innes included, only contains nutrients for about 6 weeks (honest - it says so on the pack!) so whatever you use, the houseplants will need some help along the way: that's why we give them liquid feed, foliar feed, slow release fertiliser, an annual top-dressing of fresh compost etc: all to make up for the fact that they have exhausted all the nutrients from whatever compost they started out with.

So yes, you can use multipurpose compost for houseplants, as well as for potting up, and to summarise the Handy Tips:

Only buy a small bag - even though it is more expensive - if you only need a little.

Don't open the bag until you are ready to start using it: and if you don't use it all, close the bag tightly to keep air, water and light out of it until you are ready to finish it.

Sieve it before using it, and if it feels dry to the touch, dampen it down before using it.

There you go!

Sunday, 5 March 2017

Things you find on Compost Heaps:

I found something mildly amazing (if  you see what I mean!) on the compost heap the other day:

It's an Iris rhizome, one which was so small and ratty that  it was discarded when I split and moved a bunch of Iris towards the end of last year. 

At about that time, I decided that this compost pen was full, and went over to filling the next one in line, so this rhizome was pretty much on the top of the heap: not nicely planted in amongst it all, you understand, but lying, dry and shrivelled, on the top.

But look! It's sprouting!! Even though it's actually  upside down,  hence all the pale brown roots waving in the air (now very dry and dead), there is sufficient stored energy in the rhizome to prompt it to start growing.

Amazing!

OK, a little bit sad at the same time, as this plant has no chance of succeeding -  it  might be able to produce some foliage this year, but it will be spindly, there won't be any flowers, and without any roots in the ground,  it won't be able to store up any nutrients for next year.

But I'm still impressed that it would even try!

Here's another one - from a couple of years back, this compost pen clearly had some tulip bulbs thrown out onto it, the previous year: and look! Flowers!

I've also found sprouting Advocado stones (technically they are a berry, but they don't look much like one, do they!) in this same pen,  over the years, and I've often been tempted to pot them up and take them home... but without a greenhouse, they wouldn't flourish, so it's probably better not to.

What about you? Have you found anything interesting growing on a compost heap? Send me a  photo, there will be a prize for the best one!