The spikes will be about four to six inches tall.
You might have to get down to ground level and look.
The tiny seeds on the stalks are psyllium, the ingredient in Metamusil. Just in case you didn't know. The leaves will stop itching from insect bites and heal cuts. Just find a leaf, chew it up a bit, and apply to your skin. The leaves are the part to forage if you want to make an infusion for a healing salve.
In my pasture the yarrow is also ready to harvest. The feathery leaves will stop bleeding when packed into a wound. You can use either fresh or dried leaves for this purpose.
You can harvest the leaves or the flower clusters for an infusion. (If you click on the above photo and look at the bottom center, you'll see a creepy-crawly.)
Other plants I sometimes include in my infusions and salves are chickweed, calendula, comfrey and others, but there are so many more that can be used. Do some research and decide what will work best for your situation.
Please remember that your health is your own responsibility!
There are many internet sites and you-tube videos with instructions on how to make infusions and salves, and with information on healing herbs. Here are just a couple:
How to make an infusion: the warm infusion method, and cold infusion method