is this in the EU/NA version of the game ?

These can no be obtained by combining Unknown Seed with Truffle Mushroom.
Unknown Seed can be obtained with very low chance byproduct in Alchemy.

In EU Truffle Mushroom Hypha cost 18.7mil silver in Market Place.
Farming one in player fence will give in average of 61 Truffle Mushrooms (I harvested 10 Hyphas to get numbers).
Truffle Mushroom market value is 187k/pc, so Hypha cost about 100 mushrooms.

Manual gathering will be much easier and faster than wasting 10 grid farm fences for this farming, specially when Hypha cannot be breed.

The market doesn't have it so no you have to gather it with a hoe. The Truffle Mushroom i mean

That's all i know: http://forum.blackdesertonline.com/index.php?/topic/95326-the-missing-hypha-truffle/
And if you check this, you can see in description that you can obtain Truffle Mushroom Hypha: http://bdocodex.com/cn/npc/10223/
Furthermore in the Truffle Hypha is write: " - How to Obtain: The method for obtaining this Hypha is unknown. ". That's different from others Hypha

Reported this as faulse that it's available for eu/na.

is it available or not in EU/NA?

This item has never been added to NA/EU servers
I am not even sure if it exists in KR servers. This might be one of the items that has been just added to game database, but never to players.

Picture that was posted here shows one of the locations where you can find Truffle, but Gathering Truffles wont give you the Hypha.

Hifa de trufa consegue fazendo alquimia

1x Hypha generates
40-75 Truffle
25% chance to get 1x White Truffle mushroom

Truffle Mushroom Hypha cannot be bred for more Hyphas nor higher quality... yet
It can only be harvested

Change the text to "Note that this plant will take up 10 grid in a garden."