Ornamental artillery plant, Pilea microphylla, aka gunpowder or pistol plant, military fern, or rockweed, is an herbaceous perennial.
It is one of about 600 types of non-stinging Pilea species in the Urticaceae, or nettle family.
This tropical species thrives outdoors year-round in Zones 11 to 12 as a short-lived evergreen perennial. It is also grown as an outdoor annual or indoor houseplant in all zones.
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In this article, we’ll discuss all you need to know to grow and care for your own artillery plant indoors.
It has a creeping growth habit and may reach mature dimensions of six to 18 inches high and 12 to 24 inches wide.
The artillery species has plump leaves like a succulent. They are either green or variegated pink and white, one-eighth to one-half inch long, and “obovate,” or rounded and narrower at the base. The leaves are arranged in opposing pairs, like a fern frond.
In nature, the species produces tiny pinkish flowers followed by brown fruits. And while flowering is unlikely to occur indoors, it’s fun to know about it because the names “artillery,” “gunpowder,” “military,” and “pistol” come from an unusual characteristic.
There are both male and female flowers, and the males literally propel pollen into the air, as in an aerial attack.
Historically speaking, the artillery species has undergone numerous botanical reclassifications by Swedish botanist Carl Linnaeus and later botanists, including Parietaria microphylla (1759), Pilea muscosa (1821), P. microphylla (1851), and P. trianthemoides var. microphylla (1869).
These synonyms and “basionyms,” or name equivalents and their predecessors, still pop up in plant searches, so it’s good to be familiar with them.
The artillery species is native to the Caribbean, Mexico, Central and South America, and the southeastern United States.
In its native habitat, it is a somewhat weedy, spreading ground cover that commonly sprouts between rocks and in lawns, in margins between land and water, and in masonry crevices.
The species has been introduced around the world, and is classified as invasive or at high risk for becoming invasive in many places because it readily naturalizes via stolons, or runner roots, as well as self-sown seed.
Today’s cultivated varieties are robust versions of the hardscrabble wild species. And while indoor cultivation does not pose a threat to the landscape, we do not recommend letting P. microphylla spend the summer outdoors in temperate zones as we do with many houseplants, in order to avoid inadvertently introducing it to the landscape.
This tropical species thrives best with a daytime temperature range of 65 to 85°F and 1000 to 2000 foot-candles of daylight, which is another way of saying bright indirect light.
Lower light is well-tolerated but usually causes shading to dark green, so don’t waste money on a variegated variety if you choose a dim location for your plant.
And growth may be more horizontal than upright. A little pruning of leggy stems contributes to a more compact form.
If you have a very dim setting, such as a windowless office, that you wish to add a plant to, you’ll need a grow light.
To grow your own P. microphylla, you’ll need to start from seed, take a stem cutting from an existing plant, divide an existing plant, or purchase a nursery start.
Outdoors, this is a vigorous self-sower that disperses tiny seeds with gusto, contributing to its invasive tendencies.
However, starting from seed may pose a challenge, as most retailers sell live plants and seeds can be hard to come by.
The unique and lively artillery plant, also known as Pilea microphylla is becoming an increasingly popular houseplant. Its funky leaf shapes and easy care make it a fun addition to both indoor and outdoor spaces. However properly planting artillery plants is key to getting them off to a healthy start. One common question is how deep do you need to plant these quirky little greens?
As an experienced gardener and artillery plant enthusiast, I’ve experimented with planting depth over the years. In this article, I’ll share my research and personal experience to help you determine the optimal planting depth for your artillery plants. Read on for tips on preparing the right soil, hole size, transplanting from water, and more.
Artillery Plant Growing Conditions
Before deciding on planting depth, it’s important to understand the basic needs of this species. Artillery plants are native to tropical rainforests, so they require warm temperatures between 65-80°F and high humidity. Fortunately, their small size makes them a versatile houseplant able to thrive indoors.
These plants prefer bright, indirect light. While they can tolerate low light conditions, insufficient sunlight leads to sparse, leggy growth For the best results, situate them near an east or west facing window
Well-draining, nutrient-rich soil is also vital. Artillery plants thrive in a peat moss based potting mix with added organic material like compost or worm castings. Proper soil prep sets the stage for success at planting time.
Factors That Determine Planting Depth
When planting artillery plants, hole depth depends on a few key factors:
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Root structure – Plants with large, established root systems require deeper holes than young plants or cuttings.
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Soil drainage – In dense or clay-heavy native soil, plant deeper to prevent waterlogging. In lighter soils, shallower depth is fine.
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Transplanting method – You may need to adjust depth when transplanting plants from water or other propagation methods.
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Pot size – In general, planted 2/3 the height of the container allows ample room for roots to spread.
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Plant maturity – Young plants can be buried shallower than more mature specimens.
As you prepare for planting, assess these factors to determine the optimal depth for your situation. Avoid sticking to rigid rules; let the needs of each plant guide you.
Recommended Planting Depths
Based on my experience successfully growing artillery plants, here are my general guidelines for hole depth:
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Seedlings, cuttings, or small juvenile plants – 1-2 inches deep
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Established potbound plants up to 12 inches tall – 4-6 inches deep
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Larger mature plants or those in bigger containers – 6-8 inches deep
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Bare root plants – Deep enough to accommodate the root ball
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Plants recently transplanted from water – 2-3 inches deeper than the previous waterline
Adjust as needed to account for soil type, drainage, and other variables. The key is allowing ample space for the current root structure while still keeping the base of the plant buried.
Step-By-Step Planting Guide
Follow these steps when planting your artillery plants for success:
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Prepare planting hole 2-3 times wider than the root ball or container.
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Loosen and amend the native soil removed from the hole with compost.
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If transplanting, gently loosen root ball to encourage outward growth.
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Place plant in hole, positioning it at proper depth based on guidelines above.
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Backfill hole with amended native soil, tamping down lightly to remove air pockets.
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Form shallow basin around plant to hold water.
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Water thoroughly until soil is moist but not soggy.
Managing Pests and Disease
With indoor cultivation, you are not likely to face many issues. Some common houseplant pests prefer very dry environments, while fungi and bacteria favor dampness.
Try to keep the indoor humidity at or above 45 percent, and avoid both under- and overwatering as well as direct sunlight.
Even with the best care, pests may appear. You may encounter:
Some are more likely to prey upon flora grown outdoors, but you should be aware of the possibilities.
If a stream of running tap water doesn’t dislodge the offending insects, try one or more of the following:
Treat sapsuckers and caterpillars with an application of organic neem oil.
Apply food-grade diatomaceous earth to the soil. It addresses sapsuckers as well as flying pests and gastropods, and remains in the potting medium as a preventative measure against future infestation.
Place yellow sticky tape products formulated specifically for trapping flying pests near affected pots.
In the event of an extensive infestation, you may have to remove severely damaged foliage by cutting stems just above a leaf node or at the base.
As for diseases, the following are known to afflict P. microphylla:
- Anthracnose (Colletotrichum spp.)
- Myrothecium Leaf Spot (Myrothecium roridum)
- Pythium Root Rot (Pythium spp.)
- Rhizoctonia Aerial Blight (Rhizoctonia solani)
- Southern Blight (Sclerotium rolfsii)
- Xanthomonas Leaf Spot (Xanthomonas campestris)
As we said, indoor specimens are less likely to suffer from these ailments than plants grown outdoors.
However, if yours should become infected, there are both chemical and biological treatments for fungal and bacterial conditions that you can try.
If the damage is extensive, it is often better to discard the plant and sanitize the pot with a 10-percent bleach to water solution (one part bleach to nine parts water).
From a Stem Cutting
If you know someone with a plant already, you can get a head start by taking a cutting.
To propagate a stem cutting, make your cut about four inches from the tip of a growing stem at any time during the spring or summer.
Use clean shears and choose a spot to cut that’s just below a leaf node. This is a natural growing point, where roots will readily sprout.
Pinch off the lower leaves to reveal a bare stem about two inches long.
Place the bare stem in one inch of water in a narrow container that can support it, like an old unused drinking glass. There should be no leaves below the water line, as they will start to decay and foul the water.
Place the glass in a location with bright indirect sunlight, such as near a window with an opaque curtain. Avoid direct sunlight, as it may burn the foliage and roots with its intensity.
Change the water daily.
When roots sprout over the next couple of weeks, you’ll have a cutting that’s ready to pot up, which we’ll discuss shortly.
In addition to calling upon another gardener to assist you with the cutting method to get started with your first plant, you may be lucky enough to have a friend who is getting ready to repot. In this case, you can ask for a division.
This method involves unpotting and dividing one plant into two or more sections and transplanting the sections to their own containers.
You can learn how to divide an herbaceous perennial in our guide.
If you haven’t got a repotting friend, it’s time to get your wallet out.
Pilea Microphylla Artillery plant care & Tips.
FAQ
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