Green Giant Arborvitae: Diseases and Remedies (Explained for Beginners)

NOTE: Green Giant Arborvitae may be referred to as Thuja standishii x plicata ‘Green Giant’ in this article, in fact, those are the same plants, Thuja standishii x plicata ‘Green Giant’ is the botanical name for Green Giant Arborvitae.

There are six species of evergreen trees that are native to East Asia and North America. The “Green Giant” arborvitae is a fast-growing variety. It is a cross between the Western Redcedar and Japanese arborvitae. The “Green Giant” was introduced to the U.S. National Arboretum by the D.T. Poulsen nursery.

Why does my Thuja standishii x plicata ‘Green Giant’ roots have rot?

If left untreated, root rot on your Green Giant Arborvitae (Thuja standishii x plicata ‘Green Giant’) can be fatal. For this reason, if the symptoms appear, we highly advise that you adhere to our recommendations to keep your plant alive: Blackened and softened roots.
Green

Why does my Green Giant Arborvitae have gray mold spots?

Gray mold spots are a specific fungus that regularly harms flowers and spreads swiftly. If you notice any brown (or gray) spots, this fungus is probably to cause. You risk your plant dying if you ignore these warning indications.

Our Solution

When you understand the root of the issue, the solution makes perfect sense. The majority of the time, it is caused by the Thuja standishii x plicata ‘Green Giant’ being overwatered. We urge you to cut off the infected roots and leaves, remove the affected sections of the plant, and then repot your plant in a fresh container with sterile potting soil.

Why does my Green Giant Arborvitae have leaf spots?

Leaf If your plants exhibit symptoms like rapid color changes in the leaves or leaves that wilt or droop, we give you all the information you need to recognize them and rescue your plants. For owners of Green Giant Arborvitae, this kind of illness is among the most distressing.

Why are my Green Giant Arborvitae leaves turning yellow?

In the world of horticulture, yellowing leaves are undoubtedly the most common problem. The two main causes of this problem are overwatering and a lack of nutrition.

When it’s overwatering, simply reduce your watering frequency, and if you think it’s a nutrient deficiency, here’s how to check it:

Each deficiency produces a different yellowing on the Thuja standishii x plicata ‘Green Giant’ in question, here’s how to spot them:

  • Yellow patches between leaf veins on elder leaves are the first sign of magnesium shortage. Veins continue to be green while the leaf’s core turns yellow. The leaf’s edges yellow last.
  • Another indicator of iron deficiency is yellowing between leaf veins, but young leaves on plant tops and branch tips are first affected.
  • Sulfur deficiency starts with the newest leaves, turning them yellow throughout.
  • Insufficient potassium causes the leaf edges to turn brilliant yellow while the interior of the leaf stays green. Older leaves show the symptoms initially, and the leaf edges quickly darken.
  • A broad yellowing indicates a nitrogen deficiency. Yellowing starts with older, inner leaves. Yellowing spreads as it advances, eventually touching new leaves as well.

Our Solution

According to the symptoms mentioned above, you just have to act accordingly. You can reduce your watering frequency, or fix a deficiency in Potassium, or Nitrogen, for that, you just have to buy a special soil for your deficiency, a consultant in a gardening store will know perfectly well how to inform you.

Is my Green Giant Arborvitae sunburned?

You can easily tell if your Green Giant Arborvitae (your Thuja standishii x plicata ‘Green Giant’) has a sunburn. In this case, your plant will change color, starting to turn yellow or white, much like it does on us.

Sunburned

As we saw above, the leaves of your Green Giant Arborvitae can also change color if it receives too much water or insufficient light.

However, there is a way to tell if it is sunburn; look at the bottom of the yellow leaves, the ones that have a shaded area closer to the root, if this area stays greener, it is probably sunburned, not something else.

Why are my Green Giant Arborvitae leaves turning brown?

The classic sign that a plant has been overexposed to direct sunlight and sunburned is the development of browning leaves. Rest assured that while this may probably save your plant from dying, it will adversely affect its growth.

Should I leave my Thuja standishii x plicata ‘Green Giant’ in direct sunlight?

No! If your Thuja standishii x plicata ‘Green Giant’ (or Green Giant Arborvitae) has the symptoms described above, don’t leave it in direct sunlight, that’s the reason why your Green Giant Arborvitae is in such a state!

Our Solution

The remedy, as said in the paragraph above, is simple: just move your plant’s Green Giant Arborvitae out of direct sunlight. Your plant should swiftly re-grow with this strategy and appropriate watering.

Why are my Thuja standishii x plicata ‘Green Giant’ leaves drooping or wilting ?

In most cases, this happens when your Thuja standishii x plicata ‘Green Giant’ lacks water. This is especially the case for large plants, naturally they need more water than others.

Drooping

An easy way to know if your Thuja standishii x plicata ‘Green Giant’ is lacking water is to under-weigh its pot, if it looks light, it means that the soil and the roots are probably quite dry, and therefore need water!

Our Solution

If the soil in your plant’s pot is completely dry, you will need to start by moistening it so that the roots will also benefit from the water. A common mistake is to drown the Green Giant Arborvitae right after a dry period thinking that it needs a lot of water.

This is the case, but giving too much water at once is the best way to finish it off, you should actually water the soil normally, resuming a quiet watering rhythm.

Caring Tips for Thuja standishii x plicata ‘Green Giant’

Water Occasionally

Water is necessary for your plant to live, but timing and amount of watering must be balanced. Overwatering could have disastrous effects on your own name, as we already mentioned.

Touching the soil will let you know whether your plant needs water or not; if it still feels damp, it’s generally best to wait a few more days.

Always keep temperatures stable

It is also a good idea to keep your Thuja standishii x plicata ‘Green Giant’ at a stable temperature (especially if it is kept indoors!). At GreenShack, we generally recommend staying in the 65 and 85 degrees F range. Of course, do not place your Thuja standishii x plicata ‘Green Giant’ near a source of hot (or cold) air such as A/C units, radiators or the like.

Keep your Green Giant Arborvitae Dust-Free

This one is about houseplants. Your indoor plants’ leaves get dusty just like your furniture does. The problem is that this might prevent photosynthesis from beginning, which would result in the plants gradually losing their color.

For your Green Giant Arborvitae, this would be a true descent into hell, and it would also appease the pests.

To remove the dust from the leaves of your plant, take a microfiber cloth and gently rub the leaves. You can wet the cloth to make it easier to remove the dust, but never use corrosive products (such as rubbing alcohol!)

Keep drainage in mind

If you have a tendency to overwater, you should be mindful of your drainage, and if they don’t already have them, we suggest selecting a saucer and a pot with drainage holes.

You can add volcanic rocks (or any other pebbles with holes) to the bottom of your pot in the interim if your pots don’t already have holes in them. This will help to form a channel so that the water doesn’t pool there for too long (preventing the rot of the roots!).