Im in zone 6b, so I get HARD freezes, not a lot, but just 1 week of 20s F as the minimum expected external temp is enough to kill these cool weather spring bloomers north of zone 8.

typically, grown plants are for sale at $4-$8 each in 4" pots at the same time as pansies in early cool spring. you can do this yourself at a huge discount,

I will say the ubiquitous "plant after last frost" is 100% a recipe for &$# outcome in any zone with 4 seasons that include freezing winters and hot summers
I have struggled and researched extensively to get it right and thought i'd share my results in my 2nd year because it isn't as hard as it sounds. it's definitely not "plant after last frost". Im angry at root sellers. plant after last frost will NEVER work if you have 4 seasons. my last frost is around may 15 and 60 days later it's week over 80.
These need about 120 days, or 5moths that don't get below 30 or over 80 to do well in the ground and outside of the pacific northwest- who has half a year not freezing or baking?

all three of these, ranunculus, freesia and anemone are native to places with very low temperature variability.. coastlines of warm seas. none can survive an in ground freeze - but all 3 can tolerate short periods of below freezing weather, even exposed foliage down to about 27.
Rather than summer and winter in their native habitats, there is a dry season and a wet season- this is almost an oxymoron, because the "dry season" is full of hot weather, strong sun and transient brief intense thunderstorms nearly daily then the sun comes out and drys everything to a crisp. In the wet season it almost never rains, but has a consistent high humidity/fog/slow drizzle with short days and cool temps so the ground stays consistently moist and the air cool. This wet season w/ little rain, cool temps and consistent 90% humidity is the sweet spot for these. they grow best in the moderate "winters" of a tropical location that experience a "cool wet season" with little rain, low temps and high humidity.

I live right outside NYC, in zone 6b. I have 4 seasons, all of them brief, without the long term temperature stability that these beautiful flowers get in their native soil.
last year I did a ton of research and had a good outcome, although it was late in the year when I put them outside. I took what I learned last year and this year it looks great to have a fabulous outcome. they will grow in 40 degrees, they will survive 20 and they bloom best under 75.

if you can, plant them now! i soaked and potted 1/1 - and I've found my experience doesn't align with advice from my suppliers about mandating cool to generate sprouts
Iwill come back to report data on suppliers, order dates, corms I dried from last years plants, and the outcome based on temperature data and artificial lighting..

if you are in a 4 season, start them now if you haven't already. , provide artificial light- not enough light to support photosynthesis, just enough for them to feel a fake 12 hr+ day

another issue I will address is timing of orders from suppliers (july summer sale of very inexpensive spring inventory vs pre-order of winter inventory and comparison with my own saved corms from last spring, e.g.how long can you store a dry corn you pulled out of your yard vs spummer sale of unsold spring corms delayed for 18 weeks vs fall corms...

if you read this far- you have enough information to decide to grow them or not, and hopefully to understand if you live in a 4 season location, buying corms in mid March will not be ready to bloom until mid June, when it's already too hot for these plants