Plant of the month - February

Libertia peregrinans



I discovered this plant through Christopher Lloyd, who writes about it in his book, "Succession Planting for Adventurous Gardeners" - something of a bible of mine. Anyway, as so often with new (to me, anyway) plants Lloyd suggests, it's quickly become a firm favourite of mine.

It's what they call a good do-er - rarely needs any particular TLC, tough as anything, evergreen - or should that be evergold in this case? - and just does its stuff all year round. It's an excellent plant for structure - I've got it planted between a Spiraea japonica "Gold Mound" and a Pinus mugo, where it retreats into the background a bit in summer and then at this time of the year (and indeed for most of the winter) really shines out. It has a lovely, warm burnished bronzey-gold colour that glows in low sunshine and makes those sword-like leaves shoot up, shining, from the surrounding plants.

Mine is still a young plant, but I'm hoping if it's happy it'll form a nice beefy clump in time. It almost seems like an afterthought, but it does also have pretty iris-like white flowers later in spring, too.

Rambling on

I'm coming to the end of the rose-pruning season at the moment and thank goodness for that - my fingers are full of thorns and my hands are so scratched it looks like I've been washing in barbed wire.

I'm ending the pruning season with a really tricky one, though: in my new garden, there's an old and rather dilapidated trellis fence across the back supporting three climbing roses - or are they rambling roses? That's the problem. The owner knows what one of them is - it's Albertine, which is a rambler, so that's fine. The other two are a mystery, and they're not the same as each other, either.

The difference between a climber and a rambler is quite a subtle one, but has quite an impact on how you look after them. As a general rule of thumb, if your rose is producing lots of whippy stems from at or near the ground, it's almost certainly a rambler: if you can see a framework of branches in the centre, from which the flowering shoots are coming, then you've got a climber.

Of course, there are, as always, exceptions to the rule, and I think I may have one here. The rose on the left-hand side is producing lots of long, whippy stems - but it also has quite an established framework. Now this could be because it's been quite neglected, so the whippy branches have been allowed to thicken more than they usually would - or it could just be a whippy sort of climber.

Oh dear... well, I hedged my bets and pruned it like a climber but leaving more of the whippy bits in than I usually would just in case it's a rambler after all. I shall wait until it flowers and take a sample or two up to Wisley just to find out for sure.

Oh yes, and the difference between caring for ramblers vs caring for climbers? You prune climbers at this time of year, taking sideshoots back to 2-3 buds from the central framework, but ramblers you allow to... well... ramble until August, when you remove one in three of the oldest shoots right down to the ground to thin them out a bit. Climbers, you see, flower on growth made this year; ramblers flower on growth that's matured from previous years. Which is why I'll be in deep doo-doo if I've pruned a rambler like a climber - because I'll have chopped out all those nice mature stems, and therefore the flowers... Well, time will tell, and luckily the owner is very understanding!

How to make a cold frame #1

Just occasionally I'm not so much a gardener as a builder. When you're developing a garden, the first several stages involve an awful lot of digging, lugging stone around and construction - it all seems to take ages and hasn't got a great deal to do with plants. But if you have the patience to do it, it's worth it.

I've been struggling to manage in recent years without a decent coldframe, so this spring I've decided to bite the bullet and make myself a super-deluxe model, the entire length of my 8' greenhouse and about 3'6" from front to back. This is not small for a coldframe - but then my greenhouse is already groaning with seedlings and I've only just started early sowings, so I do need the extra space!

As you'll see in the picture, the first step, before I so much as banged in a nail, was to sort out the area where the coldframe was to go. There were two blackcurrant bushes here, which were always a bit close to the greenhouse for comfort, so I moved them to the allotment this winter. I had to hoick out a spare gooseberry bush, too - not such a well-thought-out manoevre as I hadn't anywhere to put it. Luckily I've got two more to the right of this area, so I'm not exactly going to go short.

Then I marked out the area and dug it down to half-a-spade's depth. This is a really useful depth for hard landscaping - it does for paths, patios... pretty much anything, really.

Next I edged the area with boards - I used 4" boards, but you can use standard gravel boards which are 6". These were attached to short stakes at the corners and checked for straightness with a spirit level.

I roughly levelled out the earth inside the boards, and then put down some weed-suppressing membrane, stapled to the boards on the inside to about 1/2" from the top (you can just about see the edges in the picture). And, finishing touch, about 9 bags of gravel from the local DIY store. This means you can level it easily, and the coldframe isn't resting on bare earth - which means it won't rot so quickly, either.

Next instalment... the start of the woodwork!

Getting things through the winter

I was checking over my geraniums this week. I've got a few I'm overwintering for myself, plus a few for a couple of clients, and then there's another client who has a whole balcony full of them and needs them all lifting in autumn, overwintering and then setting back out in spring.

You'll hear lots of different methods of overwintering geraniums (I should say, more correctly, pelargoniums), but here's what I do. It's pretty simple.

You take the plants out of the pots they've been in all summer, and pot up in a plastic pot which just fits the roots (i.e. you don't have too much spare soil left over). General-purpose compost is fine - anything too loamy and they get too damp. Then I take the secateurs to them: any leggy stems are cut back to a bud or leaf joint about 4-5" (10cm or so) above soil level. It seems drastic, but it keeps the plants compact as they'll grow again from these points next year instead of starting a foot or two up in the air.

I give them one, very light watering, taking care not to wet leaves or stems, mostly just to settle them in to the pots. And then I switch on the greenhouse heater with the thermostat set to a few degrees above zero, and leave them to it.

I water them maybe twice the whole winter long. There are two secrets to overwintering pelargoniums successfully: first, they need to be very nearly bone dry, so once you've watered them when you transplant them, that's pretty much it until February.

Second, you need to check them over at least once a week and remove any dead or dying leaves and stems. Botrytis, or downy mildew, or whatever that fluffy mould is that grows on dead geranium leaves is murder for overwintering plants and will spread like wildfire. You need to remove the leaves regularly to keep it in check, and take them out of the greenhouse too so the spores aren't hanging around. If you do it regularly, you'll find the fresh leaves will stay fresh and you'll have greenery all winter. Harden them off carefully in early May, when you're sure frosts are past (probably a bit later further north) and you can keep them going for years.