Nopalxochia ackermannii: Unveiling the Colors of Arrowhead Lotus

Nopalxochia ackermannii, commonly known as the Arrowhead Lotus, is a perennial evergreen epiphyte from the cactus family. Its flat, lanceolate stem resembles an arrowhead, and its large flowers are reminiscent of water lilies, hence its name.

These flowers bloom from the areoles on either side of the stem, emerging from long, trumpet-shaped tubes. The flowers are double or compound, opening during the day and closing at night, each lasting only for 1-2 days.

The colors range from purple-red, deep red, pink, magenta, yellow, white, to bluish-purple. They bloom during the daytime in summer, with the flowering period from April to June.

This species generally forms a shrubby cluster, reaching heights of 50-100 centimeters. It thrives in well-lit, well-ventilated environments, but requires shading under hot, high temperature, dry conditions and is not rain resistant.

It prefers fertile, loose, well-drained soil and has a certain drought resistance. It is native to Mexico and is primarily grown in pots in China.

With a wide variety of vibrant colors, the Arrowhead Lotus blooms in the heat of summer, making it a great decoration for windows, balconies, and entrance halls to enhance the viewing effect.

I. Physical Features

This epiphytic cactus has an erect stem with many branches, forming a shrubby cluster and reaching heights of 50-100 centimeters. The main stem at the base of the plant is slender and round, with flattened branches resembling arrowheads, in green.

The stem edge is bluntly toothed. The teeth recesses have areoles, with thin spines about 0.3-0.5 centimeters long and bearing tufted short spines. The midrib of the flat stem is noticeably protruding.

The large flowers bloom from the areoles on either side of the stem, with long, trumpet-shaped tubes, double or compound petals, opening during the day and closing at night, each lasting only for 1-2 days.

The colors range from purple-red, deep red, pink, magenta, yellow, white, to bluish-purple, blooming during the daytime in summer, with the flowering period from April to June. The fruit is a globose-elliptic red berry, with black seeds.

II. Growing Environment

The Arrowhead Lotus prefers a warm, humid environment with plenty of sunlight and good ventilation. It is drought resistant but not frost resistant, and is sensitive to strong sunlight in the summer. It thrives in loose, fertile, well-drained slightly acidic sandy soil.

III. Distribution Range

This plant is native to the tropical regions of the Americas, with the most found in Mexico. In China, it is primarily grown in pots.

IV. Growth and Reproduction

Propagation through Cuttings

Cuttings are generally used for propagation. This can be done throughout the year in a greenhouse but is best done between May and July. The cuttings should be taken from healthy, robust, and plump 2a phylloclades, free from any diseases or pests.

The tissues of the current year’s phylloclades are tender and prone to rot. After the cuttings are snipped from the mother plant, use a sharp knife to trim them to a length of 8-10 cm.

Store them in a cool, well-ventilated place for about 1 day, until a thin film forms over the wound, then proceed with the cuttings. If propagating in large quantities, a nursery bed should be set up before the cuttings.

Pure sand can be used as the base substrate for the cuttings. The nursery bed should be disinfected with a 0.1% potassium permanganate solution before use.

When inserting the cuttings, use a small wooden piece to make holes, avoiding any damage to the tissue at the cut. After insertion, spray enough water and provide shade.

The temperature should be kept between 15-20°C, and the nursery bed should be kept moist but not overly wet. If the cuttings slightly wilt due to high temperatures, spray the plants with a fine spray bottle.

Generally, new roots will grow in 20-30 days, after which the plants should be transplanted promptly. For home propagation, the cuttings can be directly inserted into loose, fertile, well-drained, slightly acidic soil.

Propagation through Grafting

Arrowhead Lotus can also be propagated through grafting. Typically, a strong, healthy cactus is chosen as the rootstock. Grafting can be done in temperatures above 15°C, with the highest survival rate at 20-25°C.

During grafting, first, use a sharp steel knife to make a horizontal cut on the top of the rootstock (be sure to sterilize the knife with alcohol to prevent infection). Then, make a wedge-shaped slit at the top and flatten the bottom sides of the scion.

Immediately insert the scion into the slit and secure it with a thin bamboo needle. After grafting, place the Arrowhead Lotus in a semi-shaded area, taking care not to wet the wound. After 7 days, move it to a sunny area.

V. Pest and Disease Control

Stem rot, brown spot disease, and root-knot nematode are common threats. Control measures include spraying with a 1000-times diluted solution of 50% carbendazim wettable powder.

For root-knot nematodes, use a 1000-times diluted solution of 80% dibromochloropropane emulsion. Plants in poorly ventilated areas are susceptible to aphids, scale insects, and red spider mites.

These can be controlled with a 1000-times diluted solution of 50% matrine emulsion.

Physiological Disorders

Plants grow stems, but do not bloom

Causes:

• The plant is placed in a location that is too shady.
• The plant is watered too frequently or in excessive amounts.
• Too much nitrogen fertilizer is applied.
• The soil pH is too high.
  Insufficient sunlight and excessive nitrogen fertilizer both cause the plant to grow excessively, which is not conducive to flower bud differentiation. Overwatering hinders the efficient use of carbohydrates. A high soil pH affects the formation of flower buds.

Solutions:

Move the plant to a place with sufficient scattered light and good ventilation. Water the plant only when the soil is dry and be moderate in watering.

Apply a suitable amount of fertilizer, especially increasing the application of phosphorus and potassium fertilizers during the bud formation stage. Regularly repot the plant and change the soil to correct the pH imbalance.

Abnormal stems turning yellow, getting scorched, or wilting

Causes:

This is caused by the improper placement of the flowerpot, resulting in exposure to direct sunlight.

Solutions:

In spring and fall, the plant can be placed outdoors in a sunny location. In summer, it should be placed in a ventilated and semi-shaded place, or indoors where there is air circulation and some sunlight.

In addition, if the plant is infested with red spider mites, the abnormal stems may turn yellow. In this case, improve the ventilation conditions of the plant. Regularly inspect the plant and if an infestation is discovered, treat it with a solution of pyridaben.

VI. Main Uses

Medicinal Value

The stem can be used as medicine, with effects of promoting blood circulation and relieving pain.

Garden Ornament

With a wide variety of flower colors, the Arrowhead Lily is loved for its delicate and light posture, vibrant colors, and deep fragrance.

Primarily used for pot ornamental purposes, mixing varieties in a greenhouse can enhance the ornamental effect. It is suitable for decorating living rooms, studies, windows, balconies, and porches, and is an excellent indoor potted plant with great color, posture, and fragrance.