Succulents & Carpenter Bees

(Question)

I have some hen and chicks  in the front garden, south facing, sandy soil. Would like to add more succulents to the garden. Any suggestions on what will survive the winter and thrive? I remember seeing a spiral shaped succulent in the neighbourhood that resembled a fibonacci pattern – loved it.

The second question is that I have carpenter bees in my backyard fence, which is directly adjacent (touching) to our raspberries canes, and a brand new shed that I don’t want them to damage. Any advice on what I can do? I have no ethical dilemma in killing them (lots of bees and butterflies in the front flower garden)- but do not want to poison the berries that we eat. Also very happy to use a method that will have them move – as long as it’s not into the shed!

Many thanks,

Mike

(Answer)

Hen and chicks is the common name for several different species within the genus Sempervivum, which is, as you noted, a type of succulent.  The term “succulent” is botanical term applied to plants that that have thicken and fleshy stems and leaves.   There are over 60 genera of plants that contain succulent species.

If you want to grow succulents outdoors as perennial plants, you will need to look for hardy species that can withstand winter temperatures.  Tender succulents are often grown as indoor plants, so make sure you confirm the hardiness of candidates before you select ones for your garden.  You can determine the hardiness zone of the area you live here.

Many species of Sempervivums are considered hardy, as are many types of Sedums, also commonly known as stonecrops.  Pay attention to the botanical names when looking for hardy Sempervivums, as the common name “hen and chicks” is often applied to species in the Echeveria genus as well, which are not typically hardy.  A reputable garden centre will have a good variety of hardy Sempervivums and Sedums that come in an impressive range of colors, textures and sizes.

Your sandy soil and sunny location sounds ideal for both both Sepervivum and Sedums.  Sempervivums need well-drained soil but will tolerate poor soil.    While they prefer consistent moisture, they are shallow rooted, and the roots will rot if too wet.  Allows soil to dry out before watering.  Sempervivums need a minimum of 4 hours of light per day, and don’t do well in shade.  Sedums prefer a lot of sun and can also tolerate poor soils.  Well-drained soil is a must, and Sedums typically require little additional watering, except in the driest of conditions.  Sedum varieties come in different heights, many varieties make excellent ground cover.

In regard to your second question, carpenter bees are large heavy bees that resemble bumblebees, but with black, hairless abdomens.  Unlike honey bees, carpenter bees are not social, and as their name would suggest, female carpenter bees tunnel into wood to build their own nest that will house 6 to ten eggs per season.  Despite their boring abilities, carpenter bees do not eat wood and are considered beneficial pollinators.

In the late spring and early summer after mating, female bees will reclaim an abandoned nest or bore new nest through a perfectly round hole at the surface of the wood, making a sharp 90 degree turn after a few inches. Tunnels can reach a few inches to several feet into the wood.  The female creates individual cells along the tunnel into which the she deposits a single egg.  The female will leave a bolus of pollen and nectar in each cell (called pollen bread) for each larva to feed on until it emerges as an adult in late summer. Adults die in mid-summer shortly after mating and laying eggs.  The new adults emerge in late summer to feed, before returning to empty nests to overwinter.

Carpenter bees prefer softwoods that are bare, weathered or unpainted, so the best prevention is to paint exposed wood, if possible.  Stains do not provide any significant level of protection.  The pesticides that are typically used to control carpenter bees are prohibited under Ontario’s pesticide ban.  If you live outside of Ontario, check with a reputable garden centre for possible chemical controls allowable in your area. If you experience a severe infestation, you may want to contact a professional pest control company.

Non-insecticidal management approaches include filling entrance holes with plastic wood or steel wood and sealing with a wooden dowel and wood glue. Any adults trapped in the tunnels will not typically chew their way out, so will this may help to reduce the population in future years.  In mid-summer after the adults have died, but before the new adults emerge, you can also poke a flexible wire into the tunnel during to kill the pupae or larva before they emerge.  You may want to wear protection to do this in case your timing is off and adults are still around.  Males often appear aggressive but have no stingers.  Although usually docile, females will sting if their nest are threatened.