I would try now while leaves are off if you can't get signal now you certainly won't be able to with leaves. I believe the VHF channels may not be as affected by the trees as the UHF band .
Get the antenna outside even if its not that high it will most likely help.
Since you want the VHF high channels 7 and 11 you will need a VHF high band antenna and since these may be difficult to receive I would try the stellar labs VHF high antenna see link
https://www.amazon.com/30-2475-Fring...s%2C209&sr=8-3
A relatively inexpensive way would be to get a 21 foot long 1 5/8 inch i believe ss20 commercial chain link fence rail at a fence supplier. Hopefully you could tie it on vehicle or put on boat trailer etc to haul. These cost about $40 in my area and you can attach temporarily to hose eve 4x4 post deck corner etc or use guy wires. Later if you put antenna on roof you could hacksaw down to 12 or 15 foot for use with tripod mount etc.
Or probably easier get a 10 foot piece of galvanized conduit somewhere like lowes to use as mast pipe.
I believe you will be able to get 7 11 and maybe 8 with this antenna. I would start with antenna pointed at 134 degrees and if you get 7 and 11 but not 8 try further toward 8 at 184 degrees until you either get all three or lose 7 and 11.
If you don't get 7 and 11 there you can try on rooftop. If you get them at 10 or 20 feet above ground and lose them when leaves come out you can try rooftop.
Doubt you would need amp to try with cable less than 50 feet. If you run longer cable to put on rooftop etc and need preamp then you would need to decide if you want to combine a separate UHF with the VHF antenna. If so consider the following preamp with separate VHF and Uhf inputs to act also as a combiner
https://www.amazon.com/RCA-TVPRAMP1Z...0BPGRSKP19EZ0#
or any single antenna amp for vhf such as the LNA 200 etc
I have used climbing deer stand to climb a bigger pine tree removing limbs as i go and near top attach mast and antenna but its dangerous and a real PITA and likely would be very long cable run and possibly need power supply within 150 feet if need preamp.
I didn't mean to ramble . In short try the stellar labs antenna at a convenient height then move higher or amp as needed. If you don't get anything with this now you probably won't get it without extreme measures .
If you get 7 and 11 with stellar lab you could also consider Dennys Stacker antenna for rooftop that gets UHF and to some extent VHF high and low or something like the 7698p winegard for the VHF high and Uhf . Depends on how much experimenting you want to do with feet on ground or on rooftop.
If you have to you can always run two cables to ab switch etc but getting too complicated.