I grow allot of pearlweed all so sold as baby tears. There are two ways to trim it. If you cut the tops you can get it to grow horizontal. Take the cuttings if there over 2" and replant them in bunches of 4-5. Another way to trim is to thin them out like you would a bush. This will let them grow vertical. You said their in the front of your tank so you might want them to grow more horizontal.
Hawk
Hawk
