That's beautiful, Bob!
I've never had any leaf problems with mine, but then I've never tried to grow them in a pot. Raising plants in a pot can be difficult. If you plant your plants in a pot too large, and their small roots take in too much water from all that empty dirt around them, the plant can experience a wide variety of problems, including those that show up on the leaves. If you forget to water them, especially if they get root bound, they can get too dry and crisp up.
So I grow very few plants in pots, and for those I do, I make it a point to pot them to a pot not too much bigger than their roots, even though it's aggravating having to pot them up so often.
I plant all my pentas in the ground, knowing that they won't return the next year.
The only leaf problems mine ever experience is when the tersa sphinx moth cats eat the leaves, a good problem to me!
Sherry

Bob, the Penta lanceolata-red is my favorite plant. Period. Virtually any butterfly that likes nectar will use it and the hummingbirds love it also. They also make excellent cut flowers.

I use Banner Max and Bayers on my roses, never even thought to use them on the pentas. Let me second what Sherry said, although I know that now you need to keep them in pots because of the danger of freezes. If you leave them where they get a lot of air and sun they should be able to get rid of most diseases by themselves. I suppose the plants are too small to cut off the diseased leaves?

You have chosen well with the pentas. They are excellent for nectaring butterflies.

This is first year for me to have this problem too its so dry and hot here I have grown these forever and this year is worst year for them they useally thrive here with no care. Angie

Sherry and Tom. First, let me explain my "potting" garden. Voles are so abundant in my area, that I have been forced to utilize any means of defense available. I have used hardware cloth as a border (9" below ground and 9" above), made large "Square pots" with four sides and a bottom buried in the ground. Every method I've tried has negative paybacks of some kind. I have settled on a system using 5 gallon pots for most plants and 15 gallon pots for large ones like Buddleia. I drill additional drainage holes (Diameter 1"), plant the bush in the pot and then bury potted plant and all to a depth where about 3" extends above ground as a collar. This method has worked for me...they don't blow over in the wind and the extra large drainage holes allow the anchor roots to escape into the surrounding soil at a depth that is below the travel depths used by the Voles. Until I started using this method, I was losing between 10-30 roses per year out of about 200 that I grew. Once they are planted into the ground, they are considered as permanently placed there. The plastic pots I use are considered to be the "armor" that gets them through the growing-up years. The ability to add a month to the beginning of our growing season is a plus but as soon as the last frost date is over, they will take their place in the garden.

The below photo gives an idea of what this looks like in one of my beds.

EARLY MAY
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EARLY SEPTEMBER
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EARLY SEPTEMBER
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Thanks,

Bob

Wow! How terrible to have such destructive voles, Bob!
But you've come up with a great solution!
I was thinking about your pentas leaf problem right after I posted, and I remembered that pentas come from South Africa. South African plants need a lot of heat, and mine don't really get going good until it's 90 degrees, and they're planted in nearly full sun, so maybe it's just not warm enough yet for yours to thrive.

Sherry

Bob,

I have to second Sherry's idea regarding warmth and the pentas. I have overwintered them in my greenhouse and they look pretty ragged by spring. I trim them up, pinch off or trim the bad looking leaves, give them a feed and with the coming of warmer days, they're off and running, putting out new growth and looking beautiful once again. I've found them to be very hardy. I've grown them in both pots and in the ground and have to say they do grow much larger in the ground but also do well in large pots. The pots require much more attention due to our hot summer days but I like to have some on the deck so spend the time to give them the needed attention.

They're also very very easy to root from cuttings so if you find one that is especially attractive to your little flying creatures, take some cuttings and make more. The cuttings will grow and bloom quite quickly.

Mary

Bob,

If you have access to Liquid Seaweed, I highly recommend giving your sickly plants a good dose. I have done this on numerous plants and it just does wonders.

Ms. Faith