Peninsula Valdes has a very dry climate with very little standing water, and strong winds. Its plants are distinctively adapted to survive these harsh conditions. They are generally low and wiry, to minimize the effects of the Patagonian winds. Leaves are often small, reducing the amount of water lost to the air, and to protect this scanty vegetation against local herbivores, many of the plants bear thorns. Individual plants tend to be widely spaced and deeply rooted to make the best use of the sparse ground water.
The grasses of Valdes are tough and prickly. Representatives of the three genera, Stipa Festuca and Poa are all called "coirones".
This shrub has large thorns with which the indians once used to make needles. The leaves are small and dark green, and the fruit is purple when ripe. Burrowing parrots feed on these fruits during the months of october/ November.
The piquillin has large thorns, very small light green leaves and the fruit is deep red, sweet berry; containing several large seeds, which can be used to make jam. Guanacos, foxes, a small rodent called "cuis" and birds feed on the berries that ripen in March and are the largest edible berry.
There are two species of creosote, which are easily distinguished by the shape of their leaves. Both bend and sway freely in the wind. These species are common along the highway from Trelew to Puerto Madryn, as well as on the drive to the Carlos Ameghino Isthmus.
L.divaricata is also common in the deserts of the southwestwern United States and northern Mexico, and is called Creosote Bush in English because of the pungent smell it gives off after a rain.
Found more in rocky areas, the duraznillo has long bright green leaves. The flower is also long, thin and very dark red. The fruit for which this bush is named, is poisonus and looks something like a small peach. Easily seen in the vicinity of Punta Tombo.
There are three species of Chuquiraga, the commonest being Chuquiraga avellanadae (quilimbay). It is a low shrub, with lanceolate leaves, with a sharp thorn on the tip. Seen in great quantities near the Caleta Valdés. The indians used it as firewood because it burns even when green. Rheas are fond of the yellow prickly flowers which appear frequently in their droppings. Sheep also survive droughts feeding on these flowers.
Has long, thin, hard leaves and the yellow flowers are very abundant. It flowers during the whole summer and beginning of autumn.
Named for the tail of the armadillo, the colapiche looks like a mass of green twigs ,that when touched is covered by tiny thorns, so it may be mistaken for a cactus. The flowers cover all the branches during November, flowers being pink the first days and then turning white. While in bloom it looks like white or pink cushions. Found at Dos Pozos on road to Punta Tombo.
This hemispherical shrub is completely pale green, with leaves that divide in three (trifoliate) and pale yellow flowers. It segregates a juice which is distateful to plant eating animals.
Shrub with hard but flexible, short grey branches. Large brownish thorns up to 4 cm. long and looses its leaves in winter. Fruit: a shinny and curved blackish-red pod. This species is endemic to Patagonia.
Jume has a high salt tolerance and therefore it thrives in the salinas, and near the coast in Rawson , Punta Norte and at Punta Tombo. At Tombo the penguins nest under the large jumes. In other parts of the country the natives used to burn it and use the ashes to make soap and "mazamorra".