This is kinda spellcasting related but at the same time I'm more curious about something. Is it possible for plants to be familiars? Like- a sort of plant spirit I mean. Do plants have spirits? I'm just confused and curious and I was wondering if there was some kind of ritual or spell to see if there are any spirits trying to call out to me. I had a dream of some tree spirit that said it would be my guide, but I'm still not exactly sure what's going on. Can someone please explain to me what it means?
I think that working directly with plants, when it comes to spitirtual/energetic levels, is akin to working with crystals. There is energy, and it can have distinct feelings behind it even between different stones that are of the same type. Some would say they have a 'personality'... but not as-in intelligence. More a set of quirks or unique subtleties. Like someone's car or home. Where it has unique details all its own that other cars of the same make/year don't seem to share.
Generally speaking, an energy/spirit/being needs to have some form of intelligence behind it in order to be able to fulfill a role as a guide. The purpose is to provide not just symbolic representation but also active help. Information, omens/signs, advice, synchronicity... there needs to be some way for the entity to be able to process and understand your goals and how it can help you reach them. Including actively helping with things like spell work, energy work, protection, and the actual act of being a literal guide while in meditation and journeying internally or astrally.
Basically, a guide is an active force that works with you and your will, while natural forces/energies are only active as a result of applying will.
I would suggest looking into connecting with spirits related to natural places, such as dryads and certain fae folk, elementals, earth-focused dragons, or perhaps connecting with a collective image of the energies of earth itself like 'Gaia'.