Tharp's Bluestar (Amsonia tharpii)

Desert Botanical Garden has 600 seeds from the Texas population, and 959 seeds from the New Mexico population. Thirty-three plants grown from seed obtained in Texas have been maintained in pots beneath 30% shade for approximately 10 years. During this time, only seven seeds were produced in cultivation through hand-pollination efforts. Flowering is in April, but not always reliable on a yearly basis, even under controlled conditions in cultivation. Plans for A. tharpii include continuation of seed collection when conditions permit, and further attempts to produce seeds in cultivation.

Desert Botanical Garden has 600 seeds from the Texas population, and 959 seeds from the New Mexico population. Thirty-three plants grown from seed obtained in Texas have been maintained in pots beneath 30% shade for approximately 10 years. During this time, only seven seeds were produced in cultivation through hand-pollination efforts. Flowering is in April, but not always reliable on a yearly basis, even under controlled conditions in cultivation. Plans for A. tharpii include continuation of seed collection when conditions permit, and further attempts to produce seeds in cultivation

Desert Botanical Garden has 600 seeds from the Texas population, and 959 seeds from the New Mexico population. Thirty-three plants grown from seed obtained in Texas have been maintained in pots beneath 30% shade for approximately 10 years. During this time, only seven seeds were produced in cultivation through hand-pollination efforts. Flowering is in April, but not always reliable on a yearly basis, even under controlled conditions in cultivation. Plans for A. tharpii include continuation of seed collection when conditions permit, and further attempts to produce seeds in cultivation.

Desert Botanical Garden has 600 seeds from the Texas population, and 959 seeds from the New Mexico population. Thirty-three plants grown from seed obtained in Texas have been maintained in pots beneath 30% shade for approximately 10 years. During this time, only seven seeds were produced in cultivation through hand-pollination efforts. Flowering is in April, but not always reliable on a yearly basis, even under controlled conditions in cultivation. Plans for A. tharpii include continuation of seed collection when conditions permit, and further attempts to produce seeds in cultivation.

There are only 3 populations in New Mexico and only 1 site is known in Texas. The Texas and New Mexico sites are over 160 km apart. Threats include gas well development and environmental changes brought about by past overgrazing including erosion and increased competition with non-native species (Desert Botanical Garden 2000).

The area surrounding the canyon where A. tharpii grows in New Mexico appears to have been overgrazed for some time (New Mexico Conservancy 1989). Many trenches, some as deep as five feet and two to three feet wide, have been eroded into the southwest sid

Three populations of this species are known from New Mexico, and possibly one in Texas. Two of the populations in New Mexico are relatively large (over one thousand individuals each), while the third contains fewer than 100 individuals. (New Mexico Rare Plant Technical Council 1999)

Management is different for the two sites, but the ultimate result may be the same. At the Bureau of Land Management, New Mexico managed site near Carlsbad, plants are merely checked every year. This may or may not be beneficial, as the soil at that site is extremely friable, almost powdery and fluffy and may becoming more erosive with each subsequent visit (New Mexico Conservancy 1989). At the Texas site, plants are rarely checked, but they are fenced off from a large empty, rocky pasture. There appears to be a larger number of small-sized plants at this site than at the Carlsbad site.

Investigation into reproductive biology is needed, and molecular work to determine diversity within the New Mexico population. Size- and age-class data on these plants is needed, from germination to reproductive maturity, as the size of plants in the wild is primarily resource-dependent.

Desert Botanical Garden has 600 seeds from the Texas population, and 959 seeds from the New Mexico population. Thirty-three plants grown from seed obtained in Texas have been maintained in pots beneath 30% shade for approximately 10 years. During this time, only seven seeds were produced in cultivation through hand-pollination efforts. Flowering is in April, but not always reliable on a yearly basis, even under controlled conditions in cultivation. Plans for A. tharpii include continuation of seed collection when conditions permit, and further attempts to produce seeds in cultivation.