Pasqueflower is a perennial, so several years must pass before the roots can be used. In 1-2 years, the roots are thin and few come out. I used to use pasqueflower a lot in the past, but I couldn't get satisfactory results. In particular, it was painful because we couldn't solve the mosquito problem. Ginkgo biloba is a great help in controlling almost all pests, including mosquitoes.  

Thanks for your insight on Pasque flower. It seems that Jerusalem artichoke is the likeliest commercially viable choice to be sustainable and also it is also an income generator as well. Gingko is also not viable to be planted now due to its long maturity prior to usage.
Next question - could you pls suggest some Pasque flower root(is dried root as effective ?) and gingko leaf/berry( is dried extract as effective ?) suppliers for us to import in bulk for our short term usag (1-2 years).  

By the way, apart from Jerusalem artichoke, what other JHS plants that we can plant that has a shorter harvesting period for usage in our farm? Is Oleander life cycle short ? I'm cautious on Oleander as it need precautions on handling the plant.
My JHS priority list:
1) Jerusalem artichoke
2) Pasque flower (extract)
3) Gingko (extract)
4) Oleander?
Scale insects, Mealybugs, Thrips are major pests.
Wilt, anthracnose,scab & Phytopthera palmivora(no.1 killer) major fungal issues.