Cerura Vinula foodplant: Help!

Hello, sorry it's my first time to ask something into the forum, so I just hope the section is correct!
I got (from an Actias's user!) eggs of Cerura Vinula, but there's a problem now...a caterpillar is alredy born but where I live the principal foodplants, Willow and Poplar, are not in bloom yet, so I have no fresh leaves for caterpillar!
Can someone of you tell me another plant in bloom in this periodm I can use?...which one?....or maybe just another solution!
Thank you soooo much

Thank you for you answer!
@ Rudi: Yes, I bought them because I was sure they would hatch in few weeks, not now...:(
Anyway I found Salix, leaves are still so small and thin, but they eat them, so it's good....for the next week I will have good leaves...that's the reason why I bought, because in general I always waited 1-2 weeks for hatching

Yes of course you're right...I think we both just didn't think about this...and I though shipment would be faster...for both!
Anyway today I found a great pland of Poplar with little thin leaves and now they eat very good...so I can say this time I was luck...here we have 14 degreeeees during the day....where Spring is for good leaves???:(
Thank you guys for everything