Carnivorous plant terrarium

A reader asks: "Hi, I'm trying to set up two terrariums. They both will consist of carnivorous plants. I am considering Venus fly traps, Sundews, Butterworts, and Sarracenia purpurea. What combinations would be best for optimal growth and beauty. Also where would be a good place to buy them from. Thank you."

None of these plants are truly carnivorous in spite of what they are called. All are photosynthetic autotrophs, but all are natives to habitats, mostly acidic wet lands, where nitrogen is a limiting necessity. Carnivorous plants capture insects and other invertebrates and use them as a source of nitrogen. As wetland plants they require pretty high light and humidity, and of course, our homes are basically dimly lit deserts, a bad combination for most plants. A terrarium can solve the humidity problem. These plants also do best in low pH (acidic) conditions so that means using a growth medium high in peat moss, in fact growing sphagnum moss, sort of pre-peat, is an excellent idea. So basically you're trying to create a bog although they do not like standing in water. Sundews (pictured) do seem to like saturated soils. Tap water in most places tends to be somewhat limey, basic, so capturing rain water for your terrarium would also be a good idea. None of the plants you mention are large, but for starters it would be best to pot them individually and surround them with sphagnum, which may decide to grow if some viable asexual propagules remain. The pitcher plant can get 9-10" across, so it's the biggest. Small plants like sundew look best in clusters or clumps. Providing bright indirect light may be the most difficult problem best dealt with by putting a plant grow light maybe 18" above the terrarium.

Purchase of carnivorous plants is pretty easy. Lots of online sources are available and the Phactor tries to avoid endorsements (they refuse to pay up). Some pretty well-known sites provided without endorsement are the Carnivorous Plant Nursery, Bug Biting Plants, and Predatory Plants. They are not even uncommon in garden shops and even some big box stores. Care and feeding information is also fairly common. These are not actually difficult, but neither are they easy plants to grow successfully. One problem is the North American species are temperate, and a cold season of dormancy seems necessary to keep them happy. But feeding them flies and such can be quite a bit of fun.

Why does this oak dislike rhododendrons?

Some animosities in the botanical world make perfect sense. Tomatoes and their relatives hate growing in the vicinity of walnuts because of the juglone, but why does my shingle oak so despise the rhododendrons that grow in its shade and benefit so greatly from its accumulated leaf litter? Because of the clay content and high pH, not to mention frigid temperatures, late summer droughts, and desiccating winter winds, rhododendrons and similar semi-soft, acid-loving plants are difficult to grow here in Lincolnland, and having found a near ideal protected setting for a rhododendron bed beneath a large oak at the east end of the house, our spring display of azaleas and rhododendrons is about as good as it gets in this area. So why does this oak drop a constant barrage of limbs upon the defenseless shrubs below? Is it floral display envy? They can hardly be a worthy competitor, and yet every year one or more of the rhododendrons will get maimed, mauled, or crushed by oak limbs. Maybe this oak just has a mean dark streak deep in its heartwood, and having already had a near miss myself, the Phactor suggests that you admire the rhododendrons from a safe distance just beyond the spread of this oak's crown.