If you are talking about those yellow "plastic" stakes, you have had much better luck than I.  I have broken those things on buried rocks, tree roots, just hard dirt.  As a camp host I have picked up a jillion pieces of them, so apparently I am not the only one.  I always replace them with steel spikes, or aluminum gutter nails, with maybe fender washers to make the head a little bigger...
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OBG