Ageratum houstonianum is an annual member of the sunflower family (Asteraceae)prized in ornamental gardens for its blue fluffy flowers. Originating in Mexico and Central America it has made its way throughout the world, quickly becoming naturalized and invasive. I found this subject growing wild on a hilly roadside on Oahu right next to the previously posted Medinilla magnifica, and made a collection to photograph that night. One notable trait of this plant is that all parts contain toxic alkaloids which make it hazardous when consumed for humans, but especially for grazing animals apt to eat larger quantities of it.
Medinilla magnifica is a plant native to the Philippines which has spread throughout the tropics and has long been cultivated as an ornamental ‘exotic’ plant. It comes from the family Melastomataceae with which I have little familiarity to the point that from a list of 175 genera I only definitely recognized one (Tibouchina)!
I came across this plant growing in the wild on my first day arriving on Oahu while waiting for my check-in time at the hotel to arrive and collected it and several others in the hopes that at least one would turn out to be a native. It turns out that as with a lot of the flora especially around urban areas, this is an introduced species becoming increasingly naturalized and invasive with time. The two species of Medinilla in Hawaii are problematic because they continue to be sold by oblivious or unscrupulous nurseries and stores, and they produce thousands of tiny seeds which are spread by birds. The plant can grow as a terrestrial or an epiphyte and does well in low light conditions meaning it can displace native plants that would normally grow under the canopy or in some cases right in the crown of rare palm trees.
There’s no doubt that it is a striking plant with great aesthetic value, but after seeing so many native plants at Hui Ku Maoli Ola, Lyon Arboretum, Koko Crater, as well as while hiking, I know there are no shortage of stunning Hawaiian natives and people working hard to get them into the hands of those who are seeking botanical beauty!
Vitex rotundifolia, the beach vitex, is one of Hawaii’s native plants which grows at seashores throughout the pacific. Though the leaves look little like those of most of the mint family (Lamiaceae)this plant nonetheless belongs to that family (its flowers do look lamiaceous!) This is one of the few native species I observed in the wild while visiting Oahu on commissioned work for Hana Hou! magazine.
Considering its range, it is not surprising that this would be one of the most likely candidates to be stumbled upon in the wild, and in an inversion to the normal scheme, this plant is actually invasive in other parts of the world!
Within the U.S., beach vitex has become naturalized and invasive in the east, with control protocols very similar to the invasive Anredera cordifolia (Madeira Vine) in parts of Australia. It has some remarkable and deleterious characteristics such as promoting hydrophibicity in dunes which impacts other plants’ ability to grow and producing methyl chloride which is a chemical implicated in causing damage to the ozone layer.
Malva parviflora, the cheeseweed mallow, is a weed from the mallow family (Malvaceae) which originates from Africa, Europe, and Asia, much like the ErodiumI previously posted. It is naturalized throughout the world and where I live in California it can be commonly seen in yards, growing in cracks, fallow bits of exposed soil in industrial areas, or in roadside parking strips. Though diminutive, the flowers clearly resemble others in the family such as the hibiscuses, cottons, and the hollyhocks. This weed can be challenging to distinguish between related species, particularly due to the variable growth habit, but the fruit/seeds are a good diagnostic since Malva parviflora has a wrinkled schizocarp (a categorization of fruit with dry, fused carpels) while the most similar relative, Malva neglecta, possesses a smooth fruit.
Yet again I am presenting an invasive species which can have deleterious effects on both native plants and agriculture because it can harbor certain plant viruses and pests, competes for limited resources, and interferes with crop development and harvesting.
Originating in temperate regions of Eurasia and Africa, Erodium cicutarium, the common stork-bill has become naturalized and often invasive throughout the world. Despite the fact that California does have a native species of Erodium (Erodium texanum), I have almost never seen any other than cicutarium growing. While being annoyingly widespread and persistent, it still holds charm for me due to the magic of its seeds. I remember learning as a kid that if you got one of the fruits at just the right moment of dryness, a tiny twist or flick would set the seeds to exploding off or violently twisting up around the main stem. This moisture-driven characteristic is responsible not just for seed dispersal, but also for screwing the seed into soil as the tail finds purchase on the ground. To further add to its ability to spread, each seed is covered with stiff bristles which allow it to hitch a ride on fabric or fur, and when a lot of animals eat the plant, foliage and fruit, that’s a lot of conveyance. Sadly, this introduced species outcompetes many native plants in the same community which drives down biodiversity and even detrimentally impacts forage which causes economic ramifications. Even more unfortunately, this plant loves to be caught on fire, and can be challenging to pull one let alone thousands, which leaves only chemical options which can cause collateral damage across the environment.
I take the soil in my clean fingers and to say I weep is untrue, weep is too musical a word. I heave into the soil. You cannot die. I just came to this life again, alive in my silent way. Last night I dreamt I could only save one person by saying their name and the exact time and date. I choose you.
Was there something different about the Bradford pears this year? Did you see it, too?
Think back – back 8 weeks ago, when the nights were still chilly and the mornings were cool, but the days were warm and you thought Spring is here. There were no leaves on the oaks, but you saw the Bradford pears doing what Bradford pears do: bursting into white blooms to decorate suburban roadsides (and some…
Where I Saw It: This stuff grows all over my yard and driveway.
Can I Eat It? Internet says yes, but only in small amounts. Personally, I’m not planning to.
Native Range: Europe, Northern Africa, Western Asia.
How It Behaves in New York: Spreads quickly and according to the internet can get invasive, but can be controlled by blocking its light and/or making it sit in a bit more water than it’s used to.
Reasons to Like It: Cute ground cover, nice and soft.
