It may just be a zone 9 thing but I find Cerastium to have thug tendencies and would consign it to do its covering somewhere away from any treasures I wanted to keep. It does a great job in hard conditions - but...

One combination that works for me is bulbs and forget-me-nots. That's because the bulbs are heading up before the f-m-n is in full growth.

If you have a succulent groundcover - such as a Sedum - then the dying leaves of the bulbs can often make it too soggy, or actually smother the Sedum leaving bare patches free for weeds.

Some groundcovers emerge later than the bulbs and can draw your eye away from lots of floppy leaves. Geraniums, dwarf peas, Aquilegia, wild strawberry, for example.

It helps to have a ground cover that won't resent being disturbed every few years when you lift the bulbs to thin them and refresh the soil. Perennials are often fine, and annuals such as Calendula, Viola, and f-m-n are useful, particularly in a cottage garden setting where they can self-seed. 'All' you have to do is thin the seedlings in autumn so they don't swamp everything in spring.

Unless your summers are really brutal, sometimes you can get a good combination with sun-resistant Hostas and spring bulbs with the Hostas spreading out to cover the bulb sites, and flowering a bit later on, changing the colour sequence and values in the garden.

If you want to plant over the top of your bulb patches - you might prefer to use summer annuals which you can discard before the bulbs start to show through. Some bulbs might be sensitive to any heavy watering programme you use over summer but, if you plant water thrifty varieties, that shouldn't be a problem. Think along the lines of french marigolds and salvia and Ageratum and ask at your local garden plant store for attractive alternatives. They come in dwarf and tall.