Here is the companion list of native shrubs that thrive in the same poorly drained conditions.
As was the case with the tree list, I have a list of shrubs that I printed out from the Native Plant Society of Houston website back in July, which has now disappeared from the web.
Fortunately, someone else has posted the same lists on Livejournal--with pictures.
But, just in case that vanishes too, I include the names of the shrubs here. I have no idea who the original author is, or I would be sure to list his or her name.
Strawberry Bush (Euonymus americana) is named after its fruit which resemble strawberries (not edible). the 1" scarlet fruits remain through fall, splitting open to show orange-red seeds. this upright shrub has green stems and deciduous leaves that turn bright red in the fall.
Wax Myrtle (Myrica cerifera) is an evergreen shrub or small tree to 18'. it is extremely tolerant after getting established. the leaves have a pleasant scent when brushed against. the tiney 1/8" gray berries are eaten by 40 different species of birds. there is a dwarf wax myrtle (myrica pusilla) which gets six feet tall or less and only tolerates dry soil.
Buttonbush (Cephalanthus occidentalis) is a deciduous shrub that lives in in shallow water (up to 6") or plant in the ground. if you want butterflies get buttonbush. the late may to fall repeat blooms are perfectly round white balls with a heavy perfume. the bark has a speckled appearance and the fall nutlets are a favorite of waterfowl.
Virginia Sweetspire (Itlea virginica) has fragrant drooping white spires in spring. this 5' shrub has fall color ranging from yellow, orange, red and purple; in mild winters you get to enjoy these changing colors until spring.
Yaupon Holly (Ilex vomitoria) is an area-native evergreen shrub or small tree to 25' with stiff branches that make a dense cover that birds like to nest in. the birds like to eat the translucent red berries which are hard so they leave them on the tree all winter. yaupon is so adaptable it tolerates sun or shade and wet or dry soil.
Possumhaw Holly (Ilex decidua) loses its leavfes and is bare all winter. however, the female shurb or small tree is loaded with red berries all winter and is a standout.
Ti-ti ("tye-tye") or Leatherwood (Cyrilla racemiflora) is an outstanding semi-evergreen shrub that will grow in standing water (up to 6") or planted in the ground. in late may the fragrant white flower spikes look like petticoats. in summer the fruits turn rust color or ivory. in fall some of the leaves turn bright red and stay on the bush making a colorful picture.
Dwarf Palmetto (sabal minor) is a hardy, evergreen, fan-shaped palm. the stems are underground and the large leaves can reach 5'. it sends up a long bloom stalk to 6', with a spray of fragrant whitish blooms then it has fruit like black grapes which birds devour.
Possumhaw Viburnum (Viburnum nudum) has white flower clusters in march which turn into clusters of tiny pink, then blue-black fruit which taste like raisins. birds love the fruits too. possumhaw has outstanding wine-red fall color.
Salt Marsh Mallow (Kosteletzkya virginica) upright, branching shrub to 6 feet; grows in wet, often saline soils. the mallow forms dense showy clumps and the gray-green pointed leaves are fuzzy. 2 to 3" pink hibiscus-like flowers bloom from june - november and attract hummingbirds and swallowtail butterflies.