Hi Sandy,
Your husband could be quite right about the cross pollination. If planted in close proximity, there will be crossing. He is however wrong about all of them looking the same. You would still get variations since it is like having babies, the mix of genes would look different among the siblings. Also, some seed could be self-pollinated and will look the same as they did this year. It is unlikely all the seeds got crossed.
If you want to save seeds and keep the varieties pure, you need to plant them father apart or only one variety each year. You can however plant different types of morning glories and have them be true each year.
The first name(genus) of morning glories is Ipomoea. The second name(species) varies. So you most likely grew all Ipomoea purpurea cultivars this year. There are other types like the Japanese ones are Ipomoea nil and they will not cross with Ipomoea purpurea. There is also Ipomoea tricolor(Heavenly Blue is a popular I. tricolor cultivar) which will not cross with the other two. So you could grow one I. purpurea, one I. nil, and one I. tricolor and have 3 varieties each year that will not cross.
There are also the other morning glory relatives that are neat that you can grow without worry of crossing also. There's Ipomoea sloteri(Cardinal Climber) it gets covered in smaller,but bright red blooms. There's Ipomoea alba (Moonflower) is beautiful if you live in zone 6 or lower. It takes a long time to flower. There's others too.
Hope this helps,
Remy

Remy, I'm confused. It's not you....believe me. Like I said, I'm completely new to this and once I start something, I just HAVE to understand.

So...I bought one packet of seed. When I opened the packet, there were about 20 seeds. The seeds were about 4 different colors. I kept 6 plants and culled the rest. The 6 plants were in 2 containers which were a foot apart growing up my pool deck. The flowers were shades of pink and purple.

So if those seeds were Ipomoea purpurea, would the seeds be different colors like that? Or since the seeds were different colors, does that mean all the seeds were not purpurea? Does purpurea produce flowers of all different colors of pink and purple? And if I wanted to have the same thing the following year, I would only be able to keep one plant, then I would get seeds of differing colors? I am so confused! Can you lead me to an article that can help me understand this type of thing? This is my first stop, so to speak, so haven't done much research besides here.

Thanks so much for your patience!

Sandy

Hi Sandy,
Don't worry, there's a lot to know!
Different cultivars of I. purpurea make different colored flowers and different colored seeds. Often the lighter flowers will have light seeds and darker flowers, dark seeds. You will notice though that despite the color differences, they are the same otherwise. The seeds look alike except for color and the plants leaves are the same heart shape and the flowers are the same 2" blooms in different colors.
Your pink ones probably had the light colored seeds. That color in morning glory seeds is often referred to as peanut butter. Without crossing, those plants will produce the same light peanut butter color seed. Since you did not collect any seeds of that color, they probably will all turn out darker next year.
You did as I figured and planted the vines very close together so it was easy for the insects to cross pollinate. If you want the same exact effect next year, you need to grow more from the packet you bought if any are left, or buy a new packet next year. Morning Glory seeds are good for a long time so you can save the seeds for longer than a year.
If you want to be able to save seeds year to year from your garden, you will have to pick out a single I. purpurea cultivar packet next spring lets say a light pink one and then lets say the I. tricolor cultivar 'Heavenly Blue' which has bright blue blooms. This won't look exactly the same as you did before, but would look very pretty. I. tricolor has the same heart shaped leaf, but the blooms are about 4' and you would also notice the seeds are larger. You could also go for a Ipomoea nil cultivar with dark red or purple blooms. With I. nil you would notice the leaves are shaped differently split into three lobes. They are often variegated too. The flowers are also in the 4" range. The seeds are also larger with I. nil.
If you have other questions, don't hesitate to ask,
Remy

Thank you so much, Remy. I get it now!!! Did not realize that to get that pretty mix of different colored blossoms, they mixed seeds of different "cultivars". Now it makes sense! I would love to know the genetics involved here. I took some more seeds yesterday, and they are all identical...black. Wonder exactly what the flowers will look like next year if I plant these. Probably all purple. Or I may do as you say and buy some other species to go along with them that won't cross. Then I can collect seeds every year and not worry.

Thanks again. I really appreciate your thorough explanation. I am happy I understand what is going on, at least to some degree. :)

Sandy