The main town on Maria's Island (home to the Owens women) was portrayed by Coupeville,
a small sea-front community on Whidbey Island in Puget Sound. Standefer decided to keep to
the palette of whites and pale pastel colors and had the entire town painted.

Tourism is an essential part of the local economy so it was decided to keep the main street open
during filming. Storefronts were covered with facades while signs informed tourists that the shops
were still open for business. The whole town became a part of the filmmaking process; one of
the local restaurants doubled as an extras' housing area while clientele at other establishments
had a grandstand view of Hollywood moviemaking.
Above text from the Practical Magic production notes

 

Welcome! Step right in and browse through Verbena Botanicals, Sally Owens'
lovely botanical beauty store. The store is extraordinarily beautiful, clean and
white in design - just what I would choose were I ever to open such a store.
The simplicity of the surroundings serves to display the products that Sally sells,
which are in themselves simple, natural, and botanical in nature.

According the October 1998 Victoria magazine article 'Casting a Decorative Spell',
the prop people spent countless hours filling and labelling bottles to display in the
store - doubtless with colored water, but I prefer to think of what other potions
Sally might have created.