Answer: It sounds like this is a fairly large area. Since it is located around your septic field, you don't want to have to drive anything over it. Generally, wildflower meadows should be mown once a year to help disperse seed of annual and biennial plants--if the area would require mowing by a tractor, then I would guess you would not want them. You could, however, try a mix of perennial wildflowers. (Burpee sells a perennial mix on page 53 of their current catalog.) Pachysandra and other ground covers would be very expensive and time-consuming to plant. I think your best bet would be crownvetch. This is a legume that spreads quickly and is often used to help control erosion on steep banks. It can be grown from seed, adapts well to any soil type, and has purple-pink flowers all summer. It is quite "wild" looking--but if this is not a problem then I think it would be your most cost-effective option. Note that crownvetch can be quite invasive, so you want to keep it out of any garden beds.
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