Excessively Pernickety Neighbours

You need to study your Lease to be sure of your rights and obligations. They are as set out in the Lease, not as dictated by your neighbours. Forming a residents’ association would take the wind out of Hitler’s sails.

Our last property had communal areas for parking, bins, etc but all the "rules" were clearly set out on our Title Deeds (Scottish Law) and every knew exactly how it worked and it did apart from one. The annoying thing was that the person causing problems didn't live there!! They had bought the apartment for their daughter and were abroad for the first few months of us all moving in. Everyone was friendly and a Residents Committee was set up with monthly meetings in a nearby hotel. When the parents came back the "notes" started - on the bins, on the cars, etc. I can't be bothered going in to details as it was ridiculous . Although she didn't really bother us too much as we had a veranda apartment and own back door and rarely used the communal entrance my DH tried to have a word with her but she wasn't going to listen. However they came to the next meeting and were put in their place firmly. You definitely will have the details of your property and boundaries set out somewhere so this could be sorted out. Can't believe the other residents have condoned his behaviour and rules. I certainly would be putting out my washing in my own back garden!!!!!

Regarding the neighbours, if the builders have said, ask them to call me, then tell neighbours to do so. Then just smile sweetly!
Regarding plants and drying greens, this would have been in your lease so you would have been aware of it before you moved in. Most places with communal areas usually don’t allow ‘personal use’ of those areas eg putting up washing lines.

My flat is bought as is their flat

Do you rent your flat from a management company? Our flats are all owner occupied, we have a residents committee and they appoint a factoring company to maintain the building and gardens. This external company has absolutely no say in what residents do or do not do.
Just smile and walk away from this man.

When someone (rarely?) speaks to me in this way, I smile and thank them for their opinion, then move on.
As others have said ignore him. Should the harassment continue, you sound as if you could point out that it is harassment and you will not put up with it.
I wouldn’t mention any legal escalation at the moment, see if he leaves you alone after tackling him.

I am in the UK.
The plants would have been outside and not on the internal stairways.
The items are placed on an outside communal area .
This man has a reputation for butting into everything but so far has never been seen taking on a man.
The management company do not take anything to do with personal issues only deal with communal matters

If, at it seems to be, a block of flats, then there may be rules as to what can be put or left in the public areas. These will have been notified to you when you moved in. The Management Company will be the ones who have the authorisation and responsibility of reminding people about these rules and enforcing them.

So, politely, listen to this man, smile sweetly and ignore him. Not worth having arguments, just take absolutely no notice.

With regards to plants, etc in communal areas, there may well be rules banning these enforced by fire safety.

When you are having contractors in to carry out work in your home, it can be a good idea to inform the Management company about this in advance.

Are you in the US? Your post doesn’t read as though you’re in the UK. If you’re not in the UK it’s difficult to advise on what your rights might be.

I’d say as little as possible and just ignore them. Unless there’s anything in the official paperwork (e.g. in a lease) there’s nothing they can do.

My widowed elderly FiL moved to a development of small new houses, where an officious neighbour informed him that net curtains at front windows were obligatory, and he was not allowed to hang washing in his back garden, either.

They were her own ‘rules’ - her idea of what was or wasn’t ‘nice’ - so naturally he ignored them.

Good advice icanhandthemback. What a miserable attitude. Surely the residents association is in charge rather than this restrictive couple. It's very nice to see plants and personal items on communal landings. In our flats each landing is very different depending on the various occupants.
Good luck dealing with them. Let us know how it goes.

If his wife spoke to you , seems like he may be like this with other people aswell ... hard as it seems ignor him ... could he be jealous you are having things done who knows ? Yes surprising how many will speak to a woman & not a man ... 3 days is not long even a few weeks isn't

You do not have to put up with this. Is there a Residents Group or a Housing Society you can talk to? The other thing you can do, is ignore them. Tell them you consider this harassment and will be taking appropriate action if they continue. They are working on bully boy tactics and will probably crumble if you stand up to them legally.