In my previous garden, I lost quite a few plants after heavy downpours. My soil was really heavy and drainage was terrible. Your plants look like mine did when they drowned.

How is your drainage? What kind of planter is that? And do you water on a schedule, or do you let the soil dry out slightly before you water again? Do you water until water escapes through he bottom -- does it have holes?

Also, fertilizing every 10 days is too often unless you're using a very weak solution! If you don't have a way to flush the container on a regular basis, the salts from the fertilizer will accumulate in the potting mix and burn the roots.

Could we verify whether these plants are in a container? Or is this just a narrow flower bed?

it probably doenst matter here.. but i dont think anything needs fert every `10 days ... especially if water doenst flush old nutrients out the bottom of a pot ...

they are plants.. not children ... they dont need to be fed constantly .... unless the way you water.. washes excess out of the soil or media ....

and water when they need water .. taking into account rain ... not on some random schedule ... lets plans near dry before the next deep watering .... and you have to figure out how that works in your soil ... wherever you may be ... add big city location to every post ... when discussing outside plants ...

could we have a pic of the whole planting .. instead of just individual plants??

ken