Plant of the month: September

Amaranthus paniculatus 'Marvel Bronze'

This was a bit of a discovery this year: I've grown the droopy Amaranthus caudatus many times, both the species and 'Viridis' which is an elegant shade of green, but they tend to be quite difficult to shoehorn into a mixed border, being one of those shapes that demands a space all its own. So then I was given a packet of seed for this variety last spring, and since I hadn't got round to buying my usual Amaranthus, I bunged these in instead.

The species is the key: they're a paniculatus, not caudatus, and this means they're upright. And I do mean very upright: they're currently marching through my borders like so many purple soldiers, waving those plum-coloured pipecleaners aloft: sometimes straight upwards in tufts like eccentric feather dusters, and at other times sending up individual spires which twist bewitchingly in all directions.

The extraordinary thing for something with such chutzpah of its own is that it goes with absolutely everything. I've got one patch next to some dahlias - that purple foliage is almost indistinguishable from that of a purple-leaved dahlia from a short distance, so they blend in perfectly and make excellent partners. Sadly the dahlias are having a little break from flowering at the moment - pesky earwigs - but I have one which is a pale pink-tinged white above purple leaves which looks fabulous with the amaranthus, like white dinnerplates among volcanic plumes of purple smoke.

In the same border are pink cosmos, made all the more frilly and feminine by all that brooding purple, and vivid orange Californian poppies which scramble around under their purple skirts with true pizazz. Actually I haven't found a single thing they clash with so far. I'm a total convert: must sow more next year...

Flowers for cutting

I thought I'd say a bit about my cutting garden, as it's this year's project and very much at the front of my mind just now.

I've carved out a more-or-less square plot, about 19ft x 19ft, on the far side of my greenhouse where it's pretty sunny most of the day. It's overshadowed by a large goat willow, but not too badly, and I'm in the process of raising the willow's crown so it doesn't cast too much shadow.

The design is quite simple: a 2ft bed around three sides of the square (the fourth is for my greenhouse and coldframe), with two 4'6" wide beds across the middle. It'll all be enclosed in 1" x 4" pressure-treated timber to define the beds and make maintenance easier. There are also 30" paths around the beds for access.

The area was previously a herb garden (a bit ott since I had it in mind once upon a time to set up a herb nursery - then realised how much work was involved). Result is I need to dig out large amounts of lemon balm, chives and lovage before I can plant. The good news there, though, is that the soil is in good heart as it's already been dug over and improved once.

So far I've got lavender and Rosa gallica officinalis, also known as Apothecary's Rose, along one long side, for drying as pot pourri; the short side will be for perennials for cutting - so far a clump of asters dug up from the main herbaceous border, but I'll be adding bulbs (daffs and tulips), a statice (great for drying) and whatever else I can find. I've added a Chimonanthes praecox (wintersweet) in the corner - again rescued from imminent suffocation in the big herbaceous border - thinking I'll cut branches if ever it gets around to flowering (they're notoriously slow to settle). Along the front edge will be dahlias, chrysanths and any other late-season perennials I can think of.

In the centre beds, so far there are only sweetpeas climbing up rustic hazel poles: but my antirrhinums are chomping at the bit in the coldframe waiting to be planted out, and I've got plenty more coming on to join them there. It just needs me to keep up with them by digging out a home, and we'll be raring to go!