ANSWER - Smells are commonly linked to spirit activity and interestingly the smell you mention - flowers - is one of the most often reported smells. The fact that you didn't experience the smell on every occasion upon which you sensed the spirit's presence also makes me inclined to think your experience is a genuine interaction. A mundane source of a smell is likely to be either constant or have a specific cause that can be traced. A smell associated with a spirit is plausibly intermittent with no other obvious explanation.
I'm interested in whether the spirit is attracted to you or to your former home. There is a difference between a spirit that follows a human (no, I'm not talking about possession) and one which is bound to a place. The fact that you have experienced the interaction so rarely since you moved out would suggest that it is the house rather than yourself that is the issue here. If you've only experienced the spirit when visiting your former home then I'd be confident to say this is definitely the answer. If this is the case then any future contact will need to take place in the home where you used to live.
Though I'm not certain that even if you have experienced this spirit outside your former home that approaching it on the territory where you felt its presence most strongly may not be the best way forward anyway. If you formed a bond when living there the familiar territory may make it easier for you both to open up the channel of communication. There is also a natural protection inherent in the parental home (due to your parents subconsciously projecting their desire to keep you safe) so not only are you likely to have more luck making contact there you are also likely to be safer when doing so.
I have to be honest though, you ask for the safest way to explore further understanding and/or contact but the safest thing you can do is to chalk it up to a childhood experience and walk away. I’m not averse to the idea of contacting spirits but I do think it is important that you question your motives for wanting to do so. Are you willing to consider the possibility that you will attract the interest of this entity again? As an adult you will be more aware of the philosophical issues raised by contacting the otherworld (children tend to be far more accepting) – how will it change your world view if you end up re-establishing contact. Will it change who you are?
I’d also offer the practical word of caution that sometimes spirits (both genuine and imaginary) are attracted by times of unhappiness and trauma. Would this step into your past reawaken any problems you have put behind you? Is there a reason you’ve moved on and perhaps don’t need this in your life anymore?
Curiosity of course did much more than kill the cat – it inspired the witch as well and no doubt you’re unswayed by my warnings. Well that’s fair enough and I’ve got a couple of practical suggestions to make if you do decide to go ahead. The first is – make contact during the day. There is nothing at all to suggest that spirit interaction must be a night time thing and in fact making the setting “atmospheric” serves only to make the seeker nervous and jittery. Great if you’re a fraud trying to fake a seeing but unnecessary for genuine interaction. Make contact with simple direct words spoken out loud and ask for tangible evidence of a presence (knocking may seem a bit clichéd but can be a useful method).
Salt the doors and window frames before making contact so the contact is contained within the single room. Lighting a white candle at the highest point in the room is considered a form of protection when summoning.
Be clear about what you want to achieve – are you looking for answers? A renewal of friendship? My advice would be to proceed only when you are certain exactly what it is you are looking for.
Conclude the session with a firm direction as to what you want to happen now. Be clear if the spirit is welcome to stay, to follow you or whether it must find a new home.
When the session has finished, take a salt bath to ensure you are not taking any traces of its energy back with you.