Cocoa hull mulch (06/04/22)

Surprising at it may seem, I did not apply any mulch for the last two growing seasons. I find bark mulch especially to be too coarse (both visually and physically) for the amount of annuals and tropical plants that I use in my landscaping. I’ve taken to substituting bark mulch’s primary benefits (weed suppression, moisture retention, and composting) with frequent watering and weeding during a given week, and liberal applications of composted manure every spring. For me, bare soil has provided a more uniform surface to flower beds that does not inhibit planting of new annuals or visually distract from fine-textured plants. In a prior residence where oak leaves were plentiful every fall, it was simple enough to bag them for storage over the winter; emptying them in the spring onto a driveway and running a lawnmower over the leaves to grind them into small pieces. This ground leaf mulch worked great on annuals and tropical plants by providing moisture retention and increasing soil organic matter over time. It looked very uniform and enhanced the appearance of the flower beds, too.

This approach would not be suitable in my current location, as I have no access to bags of leaves in the fall and howling winds that would blow them away even if I did have a source. But recently, on a trip to a garden center, I rediscovered what I hope is a good alternative. This alternative is cocoa hull mulch, which is made from the hulls of cocoa beans and has a great uniform texture for beds that are meant to showcase unique and uncommon plants. It also smells richly of chocolate, perfuming the air around the flower beds.

Elephant ear framed vividly against cocoa hull mulch

The major downsides to this mulch is that it is toxic to dogs and cats, who need to be prevented from ingesting it. It is also very expensive at just over $10 per cubic foot. I ended up applying just short of 4 cubic feet over the three small flower beds that I maintain, to a depth of 1 inch on top of the soil.

Cocoa hull mulch on a bed with a Bottle Palm as the central feature. I still have chicken wire around flower beds, but will remove it in the next week as the plants are growing vigorously.

The look and smell is excellent in my opinion, providing uniform texture and color against which tropical foliage pops dramatically. The mulch looks particularly nice in the bed above underlying cannas of varying foliage colors. It remains to be seen how easily cocoa hull mulch can blow away: recent rains have compacted it on the soil surface and I’m hoping this will prevent it from drifting during dry periods.

I’ve recently had a couple of questions that I’ll repost here as others might find them useful:

This tree trunk recently split during a storm, can anything be done to save the tree?

Split maple trunk following a storm due to a ‘split leader’ growth phenomenon

Unfortunately not. When a tree splits this severely right down the trunk, it is most likely destined for a slow death. The tree has basically had half of its water and nutrient transportation system severed, and will not be able to sustain its current growth. The tree in the picture appears to be a silver maple, which are especially prone to this kind of splitting if not pruned correctly when they are saplings. Silver maples tend to produce ‘split leaders’ (where the young trunk splits into two competing trunks) early in their growth. On young trees, any ‘split leaders’ need to be pruned so that only one leader is selected. There was nothing to be done for this tree, the main fix needed to happen at least 10 years before this damage occurred.

Some of my dahlia tubers had small leaves after forcing. Can I still plant them in the ground?

‘Firepot’ dahlia (lower left corner) that is significantly behind other assorted dahlias in its growth. This ‘Firepot’ tuber had miniscule shoots when it went into the ground, while the other dahlias had much larger shoots.

I now say yes, but it is not ideal. I also had a couple of dahlia tubers (‘Firepot’ and ‘Tom Edison’) that were very slow to send out shoots this year on account of the cold, cloudy spring despite being forced indoors. When it came time to plant all the tubers back in May, I just went for it and stuck these two in the ground despite having only miniscule shoots that were around 1 centimeter long. They appear to both have grown more vigorously over the last few weeks, but are notably behind the other dahlias that had 4-5 inch shoots at the time of planting. So as long as there are signs of growth on a tuber I’d say this is ok but not ideal, as a tuber that is not growing vigorously when it goes out into garden soil will always be at a higher risk of rotting.