By saying you have mats you must have the hybrids which are different from the rhizomatous aethiopicas. When they are dormant is the time to divide them. I cut them apart with a sharp serrated knife trying to get at least one large tuber with each group. Let them air dry until the cut edges dry completely.

A lot of advice has been given on how to make them flower again- more sun, bulb fertilizer, etc. but for me letting them go dormant for 8-10 weeks after flowering s the most reliable. I do this twice a year- once in the winter and again in July so I get flowers twice a year. They hate the Texas summer heat and humidity and are subject to all kinds of rot when the daily temperature is is the 100-110ºF range.

Steverino, thanks for the answer. Yes these are Zantedeshias, not Aethiopicas. The bulbs are all the same size laying side by side and about the size of a thumbnail. They are not quite 1/2 inch tall. It forms a tidy, perfectly flat 'mat' effect. When you let yours go dormant twice a year, what procedure do you use? Do you totally stop watering or just decrease? Do you stop or decrease the watering before the foliage has all died back? Do you start watering after a certain length of time to start them growing again or do you wait until they sprout on their own?

Steverino, Zantedeshia Pentlandii

Hi- pentlandii is one of the species used in the hybrids when they are developing new yellow or golden varieties. The tubers are smaller than the hybrids but still benefit from dividing to give the roots room to spread laterally.

After flowering in spring I water them to keep them growing until the foliage starts to yellow with the onset of hot weather. That can be as early as June here. They may not show such obvious signs of wanting to go dormant in late autumn so I just stop watering to force them into dormancy. I've never had any of them except aethiopica in the ground start growing again without watering them to keep them evenly moist.

Pentlandii behaves like it wants to be winter growing here but light frosts and extended cold weather knock it back if not taken inside.

Can I just mention the spelling? ZantedesChia.

And aethiopica is a species of that genus ie Zantedeschia aethiopica, not Aethiopica by itself.