Monday, May 27, 2013

Visiting Northern California: Flowering Agaves!

Variegated Agave americana , Ruth Bancroft Garden, Walnut Creek, California
Variegated Agave americana sending up flowering stalk,
Ruth Bancroft Garden, Walnut Creek,
   Agaves (asparagus family, Asparagaceae) are a fascinating group of plants. Many have a life cycle in which they grow as a cluster of leaves (rosette) for years, then send up one huge flowering stalk. The tall stalk produces lots of flowers and seeds, using all the energy stored by the plant over the years. When the seeds are ripe, the exhausted plant dies.

   An hour east of San Francisco in the Ruth Bancroft Garden in Walnut Creek, big agaves were flowering in mid-May, 2013. Wow!

blooming agaves
blooming agaves
  Agaves, for example Agave americana, are called the century plants. However, as staff member Carol Babst pointed out, the century plant name is a misnomer, since agaves rarely live more than 25 years.

   You might not know how old your apple tree or lilac bush was when it died, but since the agaves flower so dramatically and die, people pay attention to their age.

    The flowering stalk is spectacular--10 or more feet high. But equally impressive is that after waiting 15 or 25 years--a long time to wait to flower!--the plants dies. One time to flower only.

    It seemed to me that a lot of agaves were blooming at Ruth Bancroft Garden and Carol agreed, saying that an impressive 26 individuals were in bloom.

Monday, May 20, 2013

Plant Photo Album: Plants High Above Honolulu

Hills above Honolulu
Hiking the hills above Honolulu
    Plants from around the world have been introduced into Hawaii, hundreds of them.  Visitors, walking through touristy areas, see big, colorful tropical plants, but very few of those plants are native Hawaiian species.
View from trail, above Honolulu
View from Trail
   However, all the Hawaiian islands are surprisingly rugged, with remote areas that are hard to reach.  AND there are hidden pockets of natural vegetation close by.

Monday, May 13, 2013

Plants of the World: Every Plant is Native Somewhere

California poppy in California grasslands
California poppy
in California grasslands
Tortuguero National Park, Costa Rica
Tortuguero National Park
Costa Rica
      Every plant is native somewhere! That is a truth that eventually strikes the traveler. For me, it was seeing plants I knew as houseplants  growing up a tree in the rainforest of Costa Rica.  
    Whether the plant is grown as a house plant or raised for its fruit or planted as a shrub to brighten the yard, it has a home range somewhere where it can be found growing naturally. 

     (There are a few domesticated plants whose the wild relative has gone extinct, but those are exceptional cases and today I want to talk about the vast majority of the world's 330,000 species of plants.) 

     Where plants are native they don't need human help to grow and reproduce. There, they can be found growing in odd locations--along a fence, on an eroding slope--because they got there by themselves. 

    Do you know the homelands of the plants around you?

Monday, May 6, 2013

Botany Rules 3: Why do Botanists Always Tell You the Plant Family?

choke cherries, Rose family, Rosaceae
choke cherries, Rose family, Rosaceae
        People writing about plants are forever sticking the plant family into the discussion.
Ipomoea, plant family Convolvulaceae, morning glory family
Ipomoea,  Convolvulaceae,
morning glory family

      The photo to the right is a morning glory, Ipomoea (morning glory family, Convolvulaceae)

yarrow, Achillea millefolium,  Asteraceae, sunflower family
yarrow, Achillea 
sunflower family
   To the left, yarrow, Achillea millefolium, (sunflower family, Asteraceae)

    That intended to be helpful. There are at least 300,000 species of land plants. Nobody knows all 300,000. They are organized into classes made of orders, made of families, made of genera and species. Most of the land plants, about 280,000 species, are flowering plants, angiosperms, and are in the same class. There are approximately 60 orders, 400 families and 12,000 genera of angiosperms. Orders are so big that they contain very diverse plants. For example the order Asparagales includes orchids, onions and century plants. Writers include the plant family in hopes that you’ll know one plant in the family mentioned and it’ll give you a decent guess what the plant described is like.

      Here, for example, are capsule descriptions of a few major plant families, not intended to describe their characteristics as much as to prod your memory of them. Plants differ and botanists group them based on those characteristics, so plants in the same family share important characteristics while those in different families seem, and are, different.
rose, Rosa sp., rose family, Rosaceae
rose, Rosa sp., rose family, Rosaceae

   For example, members of the Rose Family have a ring of five petals around a center and produce a usually fleshy fruit with a few hard seeds inside. Lots of them are shrubs or small trees. Members of the rose family, in addition to roses, are apples, plums, apricots and pears.

Thursday, May 2, 2013

Plant Story: The dreadful field bindweed

sprouting field bindweed
Sprouting field bindweed
April 28, 2013. Bindweed!  The bindweed in my yard is up!

field bindweed, Convolvulus arvensis
field bindweed, Convolvulus arvensis
   Bindweed is the bane of gardeners along the Rocky Mountain Front Range, more than crab grass, more than dandelions. 

     Field bindweed, Convolulus arvensis, is a deep-rooted perennial vine. 

      It spreads. 

      It comes back after being pulled up. 

    I wage a war against bindweed all summer, every summer. No bindweed flowers are allowed to produce seeds in my yard. And I pull up the vines when I see them. Over and over.

    I want to believe that I have made some progress. Only two or three small plants remain in my front yard. The back yard has a lot farther to go to be bindweed-free, however, and a quick look on the 28th found dozens of new shoots just breaking the soil. It snowed all day May 1, perhaps 10” and the snow was still deep on May 2. The cold will slow them, but the war with the bindweed is on again for 2013.
snow May 1
May 1 snow

    I try to give every plant its due. Generally I let one grow somewhere in my yard and weed out all the rest of the seedlings of that species. For example, one maple seedling is turning into a nice tree, one mullein is allowed in a secluded corner, one invading sumac can have a spot by the fence. Not bindweed. After considering letting them decorate the wood pile, I decided that they could grow throughout the rest of Colorado, but not in my yard.