Always let the lilies die back naturally in fall.

Seperate every 3-4 years with oriental lilies.

Best time to do this is in fall, after the stems have died back.

I don't think that your growing conditions in the back yard are as good as the front. Add more info if you can. For instance, one is going to be a lot sunnier than the other. As well, your drainage might be different in the two yards. Eavestroughs?? Grade?

1) Maybe you should amend the soil in the back yard. Add some compost, top soil, peat moss.

2) While you should leave the foliage until it dies back naturally, you should cut off the seed heads. Just cut the stem about an inch under the lowest flower pedicel. So, your lily should be about 2/3 the height that it was with flowers on. A few years from now, you can start saving seeds and growing your own.

3)Separating bulbs that you planted closely together is not what is meant by separating the bulbs. When the lilies are happy, they will vegetatively reproduce underground. That is, they will produce daughter bulbs. Over the years, the spot that once had one lily will have five or six. Those are the bulbs that you then need to spearate, and pass on to family members, or neighbours, etc.

4) I would take the lilies from the back, and plant them in the front yard, since the front seems to be much better. At this time of year, you can transplant by lifting the bulb and as much soil as you can carry. Or, wait until fall. a)you may lose the bulb by transplanting now. b) you may lose the bulb by waiting until fall.

5) When separating the bulbs, try to preserve as much of the root mass as possible. The roots feed the bulb. If the roots are tangled, rinse with water as you tease them apart. Seems to help by dislodging the soil. Don't think that you can just rip the roots off, since the bulbs are sent to you almost rootless. They need the roots.

6) Switch to Asiatics. I know the orientals are fancier, and smell, but they are more difficult for a lot of people. Stick some Asiatics in the back yard, see how they do. New Jersey might be too hot in the summer for orientals.

7) Join your local lily society. there are a couple in that part of the States, look up North American Lily Society (Sorry, don't know URL) read what they have to say. Follow their links for more info.

I would agree that the back yard might not be the place for these lilies.

Dunwaukin is quite right that Asiatics are often easier to grow. You might also think about daylilies, most daylilies are very easy to grow and multiply quickly. There is a separate Gardenweb forum for Daylilies if you are interested in learning about them.

And don't bother trying to divide lilies until you can see that there are lots of new lily plants and they are looking crowded. (as in #3 above)

Great info. I have a lily that came as a plant, no idea how many bulbs there were, but it was supposed to be multi-colored. In the last 3 years, this lily has been a happy camper in our full sun yard and has produced various shades of pink and red, and grown tremendously. This Spring it has exploded with lily buds. I've never heard of Asiatics but I'm guessing that's what this is. I was wondering about separating it now but will happily wait until Fall. Timely advice for me!