Sad and droopy mum flowers, leaves look great!
I purchased three mum plants for the fall. Two appear to be doing great, the third, not so much. I transplanted all three into larger pots. All three pots had been previously used, two for citronella plants, the third for cherry tomatoes. The citronella plants did reasonably well, the tomato plant was both leggy (10-12’ stalks and literally a handful of marginally respectable tomatoes (most were split). The two mums that went into the citronella-used pots have done nicely, the mum in the previously used tomato pot is the item in question. The flowers appear quite droopy (almost look as if over-watered), the leaves on the other hand look nice and perky. Soil moisture levels are the same for all three plants. None of the plants get a lot of direct sunlight (little less than 3 hours) but they are in a bright location...they are next to one another. I fed all three with the same Miracle-Gro fertilizer. I pulled the rootball of the questionable mum out of the soil...it had new roots making their way out of the rootball into the neighboring medium. All three are in potting soil (the type with vermiculite and mulch-like texture). Not sure what to do. Also, the new buds do not appear to be thriving on the plant in question. Is it possible that the unknown issue that impacted the scraggly tomato plant is also impacting the mum?
Tomatoes and mums grow best in full sun in a well drained soil. However, tomatoes and mums are susceptible to different diseases and growing conditions in the containers may be different as well.
Tomatoes are fruiting plants and require a minimum of six hours for best growth. They will be more productive with 8-10 hours of sunlight. In containers tomatoes require good growing conditions, spacing, the right size containers, good drainage, may need light fertilization, can be susceptible to some foliar diseses, etc.
Here is our publication on container gardening and our vegetable profile on tomatoes
Mums - Grow best in full sun in a well drained soil. In wet seasons and poor drainage the mums can be susceptible to some diseases like gray mold and/or cladosporium. The mums need more sun. At this point in the season, you should treat them as annuals. Most likely they will not overwinter.
Maybe you can place the container in full sun and make sure the soil drains well and purchase new plants and replant