All deities have a list of prescribed (Vihita) and proscribed (Nishiddha) offerings, flowers etc. And, Lord Vishnu is also not an exception in this regard.
There are certain flowers that must not be offered to Lord Vishnu.
The book "Nitya Karma PujA PrakAsh (GitA Press)" ( on p 372) gives the names of some flowers that are not to be offered to Lord Vishnu:
What we offer to the deities is called UpachAra. When a particular UpachAra can not be arranged for, then a substitute (anukalpa) is always prescribed.
Quoting from Anhika Kritya (by ShyAmA Charan Kavi-Ratna VAridhi), first BhAga, 1st Khanda (p 30):
Substitute for honey (madhu) is jaggery; for ghee it is sesame oil;
for all things it is jaba (barley); ...