eds ▁in ▁each ▁pod . ▁They ▁are ▁ed ible ▁when ▁tender . ▁ ▁It ▁is ▁grown ▁as ▁an ▁orn amental ▁plant ▁and ▁as ▁a ▁reve get ation ▁species ▁( e . g ., ▁in ▁coal ▁mines ▁in ▁Australia ), ▁requiring ▁little ▁care ▁when ▁cultiv ated . ▁As ▁a ▁leg ume , ▁its ▁roots ▁form ▁a ▁sym bi otic ▁association ▁with ▁soil ▁b acter ia ▁known ▁as ▁rh iz ob ia , ▁which ▁transform ▁atmos pher ic ▁N 2 ▁into ▁a ▁plant - usable ▁form ▁( a ▁process ▁called ▁nit ro gen ▁fixing ), ▁therefore , ▁this ▁plant ▁is ▁also ▁used ▁to ▁improve ▁soil ▁quality ▁through ▁the ▁decomposition ▁of ▁nit ro gen ▁rich ▁plant ▁material . ▁ ▁Us es ▁ ▁Food ▁In ▁S out heast ▁Asia , ▁the ▁flower ▁is ▁used ▁as ▁a ▁natural ▁food ▁colour ing ▁to ▁colour ▁gl ut in ous ▁rice . ▁In ▁Kel ant an , ▁east ▁part ▁of ▁Malays ia , ▁by ▁adding ▁a ▁few ▁bud s ▁of ▁this ▁flower ▁in ▁a ▁pot ▁while ▁cook ing ▁white ▁rice ▁will ▁add ▁bl u ish ▁t int ▁on ▁the ▁rice ▁which ▁is ▁served ▁with ▁other ▁side ▁d ishes ▁and ▁such ▁me al ▁is ▁called ▁n asi ▁ker ab u . ▁In ▁Bur m ese ▁and ▁Th ai ▁cu is ines , ▁the ▁flowers ▁are ▁also ▁di pped ▁in ▁batter ▁and ▁f ried . ▁ ▁But ter fly ▁pe a ▁flower ▁tea ▁is ▁made ▁from ▁the ▁t ern ate a ▁flowers ▁and ▁d ried ▁lem ong rass ▁and ▁changes ▁color ▁depending ▁on