When to plant
Anemones can be started from Autumn through to early Winter (early March–late June), depending on when you'd like to time their peak flush. They typically start flowering roughly 3–4 months from planting. Earlier plantings bloom for longer with longer stems than later plantings.
Where to plant
Anemones need a nice mostly sunny spot, with decent drainage. If you'd like to extend your season in spring—a little afternoon shade goes a long way to keeping them cool and happy for as long as possible.
I typically space my anemones pretty tight together (about 10-15cm apart in the row and 20cm between rows). You could possibly space them further apart if in your general garden (vs cutting garden), but I do prefer their effect en mass planted tight in groups.
Aphids are very fond of anemones!! So need to be dealt to early before their population quickly explodes. As soon as they’re leafed up and especially once buds are spotted, inspect them regularly for aphids and deal to them promptly—my favourite control is using predator insects from Bioforce before I even see the first aphid (Aphidius & Lacewings are my favourites).
Anemones typically start flowering about approximately 3–4 months after planting and bloom for 4-6 weeks, and will go dormant once temperatures regularly get to around 20°C. They will keep flowering for the longest time, if kept harvested / deadheaded regularly.
Anemones are great long lasting cut-flowers, and can be harvested as soon as the flowers open. For the best vase-life and biggest flowers the best stage to harvest is when the flower has just started to elongate from the green leaved collar below by about ½ inch/12mm.
I have in past seasons been slightly guilty of faffing around with super fancy pre–sprouting methods that were probably more overkill than help! But then in a hurry for my last very late planting last year I just popped them in the ground as is just before a decent rain and had the best easiest success I've ever had. So here's what my new wiser self now recommends:
Field Planting Method
For field plantings, wait until decent rain is forecast and plant a day or two before hand—but equally try not to time it for weeks never-ending rain as too much rain for too long might cause them to rot before they get growing. Plant the corms straight in the ground (pointy side down), about 5–8cm deep (I like to include about 3-4cm of that as a compost mulch applied straight on top after planting), then they should start popping up about 3-4 weeks.
Tunnel Planting Method
Because undercover my tunnel beds rely solely on irrigation and always run much drier than the field, my tunnel planting method is the exact same as the field but with one extra pre–soaking step beforehand to make sure they're well re-hydrated.
To soak your corms it's important not to risk drowning them, so getting a little oxygen in the water during this process helps reduce the chance of over doing and causing rot issues.
You can oxygenate the water 1 of 3 ways:
— Frequently changing the water they're soaking in, at least every 30 mins.
— Leaving the water slightly running constantly into their container.
— Using an aquarium air pump/stones.
Whichever method you use only soak them for about 2-4 hours, until they're visibly plumper and almost double in size.
Full Pre–Sprouting method
The full pre–sprouting method takes the tunnel method one step further. After pre–soaking let the corms drip dry then instead of planting straight into the field, plant corms into trays (flats or cell trays), into damp but not wet potting soil and cover the corms with about a cm of soil, they can be planted very close together, almost touching, as this is just their short term temporary home.
Store the tray in a cool spot around 8–12°C for 2–3 weeks, making sure to keep the corms moist but not wet, and remove any that show any signs of mold and rot (there's always inevitably some).
During this time the corms will start to sprout and grow roots. Once the little rootlets are about 5–10mm long they're then ready to be planted out.
This method is a lot more faffing about, but when done right, does speed up their sprouting times, and helps sift out any corms that were prone to rot so you don't waste valuable bed space on duds.
Pre-sprouted anemone ready for planting:
We like to plant our anemones out in trenches (helps us stay straight-ish with our rows, which makes for much easier weeding/hoeing):
About a month after planting pre-sprouted anemone corms, the first flowers are always a little on the short side:
First flowers about 2 months after planting pre-sprouted corms (about 3 months after first soak/starting):
Full flush about a month after first few flowers: