Norway maple crimson sentry is a cultivar of Norway maple that was specifically developed to be a smaller version of the “Crimson King” Norway maple. It is called the Crimson Sentry because it is smaller than the King and has reddish purple foliage. Because it reaches only a mature height of 8 m, it is suitable for parks and gardens where there is not enough space for a full-sized tree.
I. Appearance and Characteristics
A beautiful feature tree, this Norway maple crimson sentry has dark crimson foliage which covers the upright branches. Growing to just 6 x 2 metres in 20 years, Acer platanoides ‘Crimson Sentry’ is ideal for small gardens and it would also make a lovely feature at an entrance or gateway. It is not only popular for its narrow form, but also the beautiful lobed foliage which turns from dark-red to rich purple in the summer and then to bright red again in the autumn.
Acer platanoides ‘Crimson Sentry’ truly lives up to its name, standing proudly and boldly upright, as if guarding the surrounding area. Ideal for tough positions, this columnar tree is tolerant of pollution and will do well in most soils. Exposed coastal positions are no problem for this handsome Norway maple tree.
II. How to Grow and Care
Sunlight
The norway maple crimson sentry has a certain requirement for sunlight and prefers a partially shaded area. In cases of exposure to direct sunlight in the summer, the leaves of most varieties will wither, so shading is required. As the plants get older and their root system grows, this condition will be less of a problem. A few varieties will tolerate exposure to direct sunlight, such as ‘Beni Maiko’ and ‘De Shojo’. Some weeping varieties can also tolerate exposure to direct sunlight, such as ‘Ao Shidare’.
Sunlight conditions will directly affect the ornamental appearance of norway maple crimson sentry leaves. In the spring, sufficient sunlight will make the maple leaves more vivid, while in cases of insufficient sunlight or partial shading the leaf color may fade. During the fall, sunlight can also affect the leaf color. For potted plants, full exposure to sunlight is recommended during the spring and the fall, with partial shading in the summer.
Temperature
The norway maple crimson sentry has good cold resistance and is able to tolerate low temperatures. The norway maple crimson sentry is native to the margins of forests in China, Japan, and North Korea, so these trees generally prefer a humid environment. Most norway maple crimson sentry plants have shallow root systems, so they should be watered frequently during the summer. For some varieties, a sprayed mist should be provided during the summer to increase the humidity of the air around them.
Watering
Originating from a temperate climate, norway maple crimson sentry is accustomed to moderate moisture levels and can tolerate short periods of drought. Its water habits lean towards preferring consistent moisture without being waterlogged. For optimal health, norway maple crimson sentry should be watered twice a week, allowing the soil to dry slightly between watering sessions. Given its adaptability, norway maple crimson sentry thrives both indoors and outdoors; however, as a deciduous tree, it’s particularly important to ensure adequate hydration during its active growing season to support leaf development.
Soil
The norway maple crimson sentry does not have many specific requirements for soil. It is a forest native, so it prefers well-drained soil that is rich in humus and slightly acidic. Its main root will extend deep into the soil, but its tiny fibrous roots will be concentrated near the soil surface, so accumulated water in the soil tends to cause root rot.
Fertilizing
Potted seedlings should be given slow-release fertilizer only. For seedlings grown in gardens, fertilizer should be applied three times a year: once in the early spring, once in early summer for the growth period, and once in the fall.
Planting Instructions
The best time for planting or transplanting a norway maple crimson sentry is following defoliation in the fall. At this time, the leaves will have fallen off so there is little transpiration and water loss can be avoided. In addition, the root system will still be growing at this time, preparing for regrowth the following spring. Transplanting should be avoided on the coldest days because cold wind can kill some of the shoots and branches. During the winter, in areas that cannot be sheltered from the wind, it is recommended to cover the branches.
Pruning
Pruning is mainly used to enhance internal ventilation, improve shoot formation, promote growth, and for shaping. The common approach to pruning is to remove any old or weak branches, remove any branches that disrupt the shape of the tree, and remove any branches that cross other branches. Pruning is used to control the plant according to the required height and shape. Generally, this follows the “Y-type” pruning method.
It is possible to prune a norway maple crimson sentry throughout the year, but the coldest winter months should be avoided to prevent damage to the plant. Major pruning to shape a maple can be performed following defoliation in the fall, or prior to leaf growth in the spring. It is recommended to prune in the fall because withered and full buds can be easily distinguished.
According to the shaping plan, you can prune any withered buds and keep the full ones, thus making your tree healthier. For pruning in the summer, diseased, weak, or dead branches can be removed, mainly to enhance the tree’s ventilation.
If grown as a potted plant, the roots can easily occupy the entire flowerpot due to the limited space. This can make a norway maple crimson sentry prone to aging if an old flowerpot is not changed. It is recommended that old roots are pruned during the dormancy period, that is, cut off any old, coarse, diseased, and weak roots.
Propagation
Norway maple crimson sentry is best propagated through cuttings, a technique which encourages the development of a true clone of the parent plant. Begin by selecting healthy, semi-hardwood segments. Cut a 4-6 inch piece of stem, ensuring it includes a leaf node. Dipping the cut end into rooting hormone can enhance root development. Place the cutting in a well-draining soil mix, keeping it moist and covered with a plastic bag to maintain humidity. Rooting typically occurs within a few weeks, after which it can gradually acclimatize to less controlled environments.
Transplanting
For norway maple crimson sentry, the beacon of transplanting success shines from early to peak spring, harnessing vigorous root establishment before summer’s heat. Choose a location with well-drained soil and ample sunlight. Gentle guidance during the transplantation ensures norway maple crimson sentry’s thriving splendor.
III. Uses and Benefits
It is a great choice for urban settings, both because of its narrow structure and drought and pollution tolerance. Its narrow spread makes it ideal to line pathways or roadways. It is also extremely wind resistant, making it a tough and hardy tree for city settings. This trait, as well as its tolerance for salt spray, also make it a great choice for coastal landscapes.
