Certainly ants do spread seeds around. Some seeds have a sugary coating especially to attract ants to carry them away to new locations. Cyclamen are good examples of this.
Sorry, missed off the latifolium bit when I posted. Used to have it , but it does not survive here for some reason.
Limomium, is what it looks like to me too!
Be careful with insecticides on Pelargoniums, many of them warn against using them on those plants as they are toxic to the genus.
Are you in the USA? Only this does not seem to be a pest generally of them in Britain.
Sneak behind the sheds and spray the weeds with strong weed killer. We had to do that in our previous garden. The owners of the land never even noticed that the weeds had gone.
Make fabulous Jam and the true Quince was the original fruit used for Marmalade.
Or perhaps Damson? Try one when ripe. If sloe then it will be bitter,if Damson then tart and sweet.
Thinking about it, coaches get there with no apparent difficulty.
Don't know about the roads, but the garden is lovely and well worth a visit.
Here is a slide show of them to whet your appetite.