I'm sorry. It almost sounds like the landscaper put some herbicide in the soil. As for a soil test, I got one from my local farmers market. There is a booth with advice from master gardener and they issue soil tests from the local university. You just mail in the dirt in the cardboard sample box, and you pay $10. Maybe you have something like that around you?

I can't think why having it landscaped should affect the garden parts. Is it possible to contact the landscaper and ask for input as to what specifically was done?

But it does sound as if a soil test is needed and they are available from your local county ag extension office for $10-15. You don't indicate your location or even your garden zone in your post (box provided for that info) or I would provide you a direct link to them. Not to mention having that info is important in answering any question. Your garden could easily have a build up of salts, low nitrogen, excess phosphorous, etc. and only a professional soil test will tell you that.

It is very possible that the garden problems may only be coincidentally related to the landscaping. There have been increasing reports of herbicide contaminated compost and manures. So if those additives were brought in from the outside that is a real possibility.

Plus since the landscaping was done have you been using a lawn service of any kind? If so them you need details on exactly what things they have been using in the area. Check with neighbors too as herbicide drift from as much as a 1/2 mile away can easily affect garden crops.

Hope this helps.

Dave