Saturday, December 21, 2013

Plant of the Month


This fragrant, woody, perennial herb is commonly used in Mediterranean dishes. Originally from Asia and the Mediterranean, rosemary is able to withstand droughts and cool climates.
It is easier to grow a rosemary plant from a cutting. The proper way to do this goes as follows:

1.      Snip 2 inch cutting from the new growth of an established plant.
2.      Remove the leaves from the bottom inch and place into a moist, fertilized soil.
3.      Place the container in a warm spot with indirect sunlight.
4.      Mist the cuttings daily and make sure the soil does not dry out.
5.      In about 2-3 weeks, test for root growth by very gently tugging on the cuttings.
6.      Once the cuttings have roots, transplant into individual pots about 3-4 inches in diameter.
7.      Pinch off the very top of the cutting to encourage it to develop branches.

Once you have your rosemary plant, make sure it has full sun, well-drained soil and a pH of 6-7.

Sunday, December 15, 2013

Winter Growing

While some growers cease planting during the winter, we're still growing strong, preparing for our spring plant sales. I spent Saturday afternoon taking dozens of cuttings of herbs and potting up plantlets of popular house plants. The greenhouse was nice and cozy compared to the outside, although it was still a bit chilly. 

Vicks, chocolate mint, lavender, rosemary and oregano cuttings
Anyways, with luck we should have tons of herbs that are a decent size for the first spring plant sale. And if they don't strike or grow fast enough, there's always aloe vera. Everyone loves aloe!

And we have lots of spider plants on hand as well. This time around, we have multiple varieties - the traditional white-striped leaf type along with the darker green cultivar and the green-striped leaf kind. Hopefully the winter won't be too cold and we'll have a good number of nice-sized plants for the sale. Venus flytraps will probably be sold towards the end of March, when it's warmer and they are exiting their winter dormancy. 

Sunday, December 8, 2013

Green Roof Update

We haven't talked much about the green roof lately, but that's not because we haven't been doing anything with it! On the contrary, we went up there about 3 weeks ago and used pruning shears to cut back the tall grass to a few inches.

Notice the tall grass towards the back
Even with 10 people we were still unable to clear all 7 beds; we finished about 4 beds and will be back to complete the job before winter break.

Low-cut and ready for seeding

Tuesday, November 19, 2013

Plant of the Month

Plant of the Month – Marigold

In honor of the Mexican holiday Dia de los Muertos, or Day of the Dead, we bring you the  Aztec marigold (Tagetes erecta) as our plant of the month! Mesoamerican culture, dating to pre-Columbian time, has always revered the marigold or the Cempasuchil for its use in celebrating the Aztec goddess of death along with the Day of the Dead holiday. Due to its strong scent, this flower was thought to have the power to awaken the souls of the deceased. Not only was this flower used in ceremonies, it was also used as traditional medicine for its now known ability to kill gram positive and gram negative bacteria. If you’re interested in growing and harvesting this wonderful flower, you have come to the right place!

The Aztec or Mexican marigold can grow to be 3 – 5ft tall. The plant thrives in warm, moderately fertile, well-drained soil. It is best to space the marigold 2-3 feet apart. If you are interested in the blooms, do not fertilize. Fertilizing will encourage the growth of foliage, not the actual flowers!

Marigolds are perfect as a companion plant because its strong scent repels most pests, particularly nematodes.  If you are looking for natural pesticides, having marigold in you garden can help you get started.

Wednesday, October 23, 2013


A few weeks ago, while a friend and I were repotting some plants for the sale, the pipe closest to the door burst unexpectedly. As far as we know, no one tampered with it, and up to that point it had shown no signs of being unsecured or loosened. Anyways, as you can imagine, water went everywhere and the greenhouse began to flood a bit.
The 'geyser' was visible from outside
I attempted to cap the pipe with the old faucet twice, only to get soaked each time. Eventually we called UH Plant Ops and they sent a plumber to try to fix it. While the plumber called for some additional help, he and I devised a temporary solution.

A bucket was placed over the busted pipe, and the stool was placed on top of the bucket to hold it down against the force of the water. Because it was unstable, we added the dolly to keep the stool in place and the water directed downward as the Plant Ops workers looked for the shutoff valve for the greenhouse water. Unfortunately, they couldn't find the valve and ended up getting wet as they fixed the busted pipe by replacing the old, weakened pipe with a new one and stronger glue.

So, the faucet is now working fine again and it is no longer leaking as well! That should be the end of the mold and algae growing around the pipe. We'd like to extend a big thanks to UH Plant Ops, since they fixed our pipe free of charge and worked well into the night doing so.

Thursday, October 17, 2013

Asexual Reproduction in Plants

A few members asked us to post the presentation about asexual reproduction, so here it is. 

Unlike humans, plants can reproduce sexually and asexually. The advantages of asexual reproduction are that it is faster, less energy-consuming, and that it produces clones of the original plant - identical at a genomic level. However, it fails to increase diversity, and any susceptibility to disease that the original plant had will be passed on to its clones.

The simplest method of asexual reproduction is through cuttings. Cut a branch off of a plant (usually an herb) that is still soft and not woody yet, remove the lower leaves, and plant it in moist soil, adding rooting hormone if desired. That branch has the potential to develop into an identical plant. This normally happens in nature when branches of a plant are broken and fall down into soil; if the branches fall into an ideal environment with the right orientation, they can continue growing and form a new plant.

Layering is a similar technique, where part of the branch of the plant is buried beneath the soil or comes in contact with the soil. The submerged part of the branch will grow roots, and soon enough that branch will be able to obtain its own water and nutrients independent of the original plant; the branch can be severed and will develop into a mature clone.

A plant’s amazing ability to regrow from almost any part is due to the fact that the shoots and roots of most plants exhibit indeterminate growth, meaning that they grow continually, and even when separated from the original plant, can still grow to form a new plant.

Some plants send out stolons or runners, aerial stems that contain plantlets (miniature plants) capable of growing roots and developing into mature clones. Examples are strawberries and spider plants.

Rhizomes are the underground equivalent of stolons. Ginger and bamboo use rhizomes to expand, explaining why many people who grow bamboo for the first time have trouble keeping its growth under control.

Suckers are almost the same as rhizomes, except that they are much shorter (usually within a foot of the 
mother plant). A new plant arises with its roots intertwined with its parent’s roots. It’s a great way to get lots of clones of a plant fast. Examples are aloe vera, snake plant, and banana palm.

Certain succulents produce plantlets at the tips of their leaves, each of which is able to form a new plant. A prominent example is the Mother of Thousands plant.

Plants with bulbs or tubers can divide their respective systems to generate clones. Daffodils, tulips and garlic all have bulbs while potatoes have tubers.

More advanced techniques include grafting and tissue cultures. We won’t go too much in detail for these, but grafting involves joining two different plants together to obtain the best of their qualities; the bottom ‘rootstock’ provides a strong root system while the top ‘scion’ grafted to the rootstock has the growing and fruiting capabilities. The rootstock is cut and the scion is attached to the cut part, where the vascular systems combine to become one. It’s the fastest way to produce cultivars of fruit trees with the desired properties.

With tissue culture, you need small pieces of leaf from the plant you want to clone. These pieces are placed on sterile agar jelly with nutrients and hormones. With luck, the pieces will develop into small plantlets that can be transferred into regular media and grown like ordinary plants.


Tuesday, October 15, 2013

Plant of the Month

In the name of Fall - our plant of the month is the pumpkin plant!

This delicious fruit baring plant is native to North America. The pumpkin is a winter squash, meaning it is an annual, summer growing plant in the genus Cucurbita. The pumpkin grows in a vine close to the ground. You can harvest the pumpkins to have volume of 15 gallons! 

If you're looking to grow pumpkins, the soil you will plant them in must be warm and filled with nutrients. Pumpkins can be greedy, so they require full sunlight, compost and a lot of nitrogen along with a weekly dose of 1 inch of water. If you're going to grow your pumpkins in Houston, it is best to sow the seeds in July.

Pests are common in the pumpkin plant. Aphids and beetles can infest your plant, a good way to get rid of the pests with out using a pesticide is to buy reflective mulch (the aphids hate that) or to introduce predatory species to your garden. Ladybugs prey on aphids, if you are using this method, make sure to provide an adequate environment for the ladybugs.

If you have any more questions, these websites provide a lot of wonderful information on care and harvest:

Thursday, October 10, 2013

Sale results

Our first fall plant sale was very successful! We raised a great deal of money that will be used to keep on supplying THS members with free soil, fertilizers, seeds, etc. and for helping with maintenance of the green roof and of our little raised garden. Here are some pictures from the sale. We couldn't have done it without the help of our many volunteers - we extend a big thanks to all of you!

Thursday, September 19, 2013

Upcoming Fall Plant Sale

As you might know, The Horticulture Society at UH is not funded by CSI or by the University of Houston. Thus, in order to raise funds for soil, fertilizer and other things, we hold plant sales every semester! Our first sale of the fall semester is Tuesday, September 24 from 10-4 in the PGH Breezeway

We will be selling everything from aloe vera to plumerias at very low prices; most plants will be $2-4, with the larger/rarer ones being a bit pricier. Many of the plants have never been sold before, so we don't know how the public will react to them, but we're hoping that they sell strong. 

Data from previous sales show that typically, people like mint, lavender, oregano and other cooking herbs, along with aloe vera. While we don't have much mint to spare, we have tons of aloe vera and some house plants that we haven't grown in years!

The Wandering Jew grows great in hanging pots or on the ground

Scented geranium - very aromatic!

The spider plant removes formaldehyde from the air

Wednesday, September 4, 2013

Plant of the Month

The plant of the month for September is the beautiful Plumeria!

This outstanding plant is native to tropical America. This small tree will only grow to be, at most, 30 ft tall while requiring a hot, dry climate. It usually takes 5 years for the tree to mature.The flowers that bloom from the plumeria are very fragrant and tend to appear between the months of March and October. 

The best way to propagate the plant is to use cuttings because this method will maintain the cultivar. The cuttings should be 1–2 ft long and should be allowed to “cure” in a dry place for at least two weeks before planting. After curing, plant them in well drained soil. Do not water too much or too often while rooting is occurring.

In Hawaii, the beautiful flowers are used to make leis. 

Tuesday, August 20, 2013

Carnivorous Plants

We've talked about carnivorous plants once in the past, but we never went into too much detail about them.

Carnivorous plants are defined as plants that obtain some of their nutrients by consuming animals. They are specially adapted to their environments, from acidic bogs in North America to the tropical jungles of Malaysia, and have different mechanisms for catching animals. While carnivorous plants (CPs) are generally divided into five types based on their trapping mechanism (pitfall, flypaper, lobster pot, bladder and snap trap), we will look at two types here - pitfall and snap trap plants.

The most famous CP is the Venus fly trap, which uses snap traps. When the sensitive 'hairs' on the inside of its traps are triggered in succession, the trap will snap shut, trapping anything inside. The more an animal (usually an insect) struggles, the faster the plant secretes enzymes that digest the insect. A few weeks after the initial closing, the trap will reopen with the empty exoskeleton of the insect still inside.

Fortunately for us, the traps never get larger than an inch or two. Venus fly traps are generally propagated through leaf pullings, though they can be grown very slowly from seed. 

There are many different species of pitfall plants, collectively known as pitcher plants. There are the North American pitcher plants (Sarracenia), the tropical pitcher plants (Nepenthes), the marsh pitchers (Heliamphora), and the Australian pitcher plant (Cephalotus). I have some Sarracenias and a Nepenthes alata growing in my backyard. 

Nepenthes alata
Insects are attracted to the pitchers due to the sweet fragrances and nectar that they produce. However, once the insects venture too far into the pitcher, they slip and fall into the water inside, drowning to death. The pitcher plant then secretes digestive enzymes, or bacteria present break down the insects into a usable form. Sometimes, small lizards and mammals also fall prey to these large pitcher plants. 

Sarracenia rubra (?)
The North American pitcher plants have much smaller pitchers and are limited to catching insects only. They operate under the same mechanism that the tropical pitcher plants use, except they grow in bogs instead of tropical environments.
Sarracenia purpurea
Like cacti and succulents, CPs are notorious for taking a long time to reach maturity when grown from seed. I have been growing two pitcher plants from seed for about two years now. They came from a Dunecraft CP starter set that included seeds of Venus fly traps, Sarracenias, and sundews, yet I was only able to get two pitcher plants to germinate. They're still quite small, so it's better to buy the mature plant unless you have lots of time to grow them from seed. 
Still less than half a foot tall after two years
CPs require a substrate that mimics the one they're used to in the wild, so you have to create a low-nutrient, acidic environment if you want your CPs to grow and thrive. There are many mixes that people use, the most common ones being 50% sphagnum peat moss and 50% silica sand or perlite to increase aeration, or 100% long fiber sphagnum moss, or equal parts of sphagnum peat moss, perlite and orchid bark for tropical pitcher plants. The important thing is to water them using distilled, deionized, reverse osmosis or rain water, since CPs cannot tolerate high levels of salt in their soil (usually over 100ppm in the water is too high). 

CPs are usually not for beginning gardeners, but growing them can be a fun and rewarding experience. And if you have sundews and butterworts, you can get rid of hundreds of pesky flies at the same time. 

Sunday, August 11, 2013

Summer Update

It's been a busy summer for us in terms of planning projects and sales for the fall, so unfortunately I didn't get around to making any posts until now.

I've been preparing succulents and cacti for the fall plant sale, so expect to see a large variety of flora there. In addition to the standard Mexican sedum (Sedum nussbaumerianum) and aloe vera that we usually propagate, we'll also have Mother of Thousands kolanchoes, some plumerias, and an unknown plant that is either of the genus Hechtia or Dyckia.

And of course, I got some new succulents that we've never sold before:
A hybrid of numerous succulent species
Graptosedum "California Sunset"

 Here are some graptosedum succulents, formed from crosses between sedum and graptopetalum plants.

A light-blue Pachyphytum
A panda plant, "Chocolate soldier" cultivar with brown tipped-leaves
TONS of cacti
And the exotic dragonfruit plant!
The "unknown succulent" that is most likely in the genus Dyckia produced seeds in the greenhouse, which I planted shortly after harvest. They sprouted a few days ago, but it'll be at least a year or two until they grow to an appreciable size. 
The tiny seedlings are 2-3 mm tall