A Gardeners Forum Forums General Discussion Plant pests and problems Oenothera (evening primrose) dying?

I planted my oenothera 'sunset boulevard' a week and a half ago and it was doing fine at first. I put it in the ground with some compost and now it is dying off quickly??? What can I do? I heard root rot can be a problem but there hasn't been a lot of moisture there. I have had to water them due to lack of rain. Any suggestion????

Mine are getting chewed up by japanese beetles!