Lysimachia arvensis (formerly known as Anagallis arvensis), is a low-growing annual recognized by its bright blue flowers and trailing square stems with soft, opposite green leaves. The flowers have a unique habit of opening only in bright sunlight and closing up tightly on cloudy, overcast days. It grows primarily as a summer or winter annual. While sometimes grown in wildflower patches or as a casual ground cover, it can spread by dropping a large number of seeds into the soil bank. Toxic to pets though tastes highly bitter, so animals will generally avoid eating it. Because of its shallow root system, it is very easy to pull or hoe out of the soil by hand.

Type: Annual

Height: 6-8", 15-20cm

Location: Sun to part shade

Seeds per packet: 25

By H. Zell - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=9021460