It is time to stop pulling rhubarb and picking asparagus. We often have callers asking if rhubarb is poisonous after the middle of June. Actually, it is safe to pull rhubarb all summer long but we stop in mid-June for the health of the plant. Rhubarb plants will feed their roots while growing the rest of the summer. It is safe to pull a small amount of rhubarb for an occasional pie or crisp throughout the summer as long as the plantings are well established. You should pull the thinnest, most tender stalks when harvesting later in the summer.
You will not be able to harvest asparagus throughout the summer as the stalks will grow their fern-like foliage and you will not enjoy eating it. The easiest way to keep the weeds out of the asparagus is to mulch it. I used some grass clippings on mine this summer.