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Get creative. Take on topics that do deal with Christmas year 'round, but in a relevant and creative way. Most importantly, take a look at how your competition takes on the topic of Christmas wreaths year 'round. Make it fun. There's always "Christmas in July" and a bunch of other fun ways to integrate the topic of Christmas wreaths throughout the year.

PS -  Load time on the site was at over 140 seconds...perhaps this is the root of the problem.

Completely agree with Bryan. Speaking from experience, the greatest results do seem to come from option 3. Yes, your main domain will probably already have some authority attached to it, but I truly believe that the main benefit is getting that fresh content directly onto the main site. By going with option 3, you give yourself the opportunity to not only add fresh content, but to focus on a variety of keywords through different blog topics, right there directly on your main website.