ro oa , ▁Pod oph yll um ▁hex and rum ▁and ▁Tax us ▁wall ich iana . ▁Research ▁plots ▁have ▁been ▁set ▁up ▁to ▁determine ▁the ▁best ▁way ▁to ▁control ▁the ▁spread ▁of ▁the ▁tall ▁H imal ay an ▁kn ot we ed ▁Pol ygon um ▁pol yst ach ium ▁without ▁dam aging ▁other ▁plants ▁or ▁the ▁surface ▁of ▁the ▁soil . ▁A ▁first ▁annual ▁survey ▁was ▁conducted ▁in ▁ 2 0 0 4 ▁and ▁will ▁be ▁repeated ▁ann ually . ▁ ▁Flow ers ▁mostly ▁orch ids , ▁po pp ies , ▁prim ulas , ▁mar ig old , ▁da is ies ▁and ▁an em ones ▁car pet ▁the ▁ground . ▁Sub - al pine ▁for ests ▁of ▁bir ch ▁and ▁rh od od end ron ▁cover ▁parts ▁of ▁the ▁park ' s ▁area . ▁A ▁de cade ▁long ▁study ▁of ▁Prof . ▁C . P . ▁K ala ▁from ▁ 1 9 9 3 ▁on wards ▁con cludes ▁that ▁the ▁Valley ▁of ▁Flow ers ▁end ows ▁with ▁ 5 2 0 ▁species ▁of ▁higher ▁plants ▁( ang ios per ms , ▁g ymn os per ms ▁and ▁p ter id oph y tes ), ▁of ▁these ▁ 4 9 8 ▁are ▁flow ering ▁plants . ▁The ▁park ▁has ▁many ▁species ▁of ▁medic inal ▁plants ▁including ▁D act yl or h iza ▁hat ag ire a , ▁Pic ror h iza ▁kur ro oa , ▁A con it um ▁viol ace um , ▁Pol ygon atum ▁mult if lor um , ▁F rit